People`s Democratic Republic of Algeria 

Ministry of Higher Education and Scientific Research 

University of Echahid Hamma Lakhdar - El Oued 

Faculty of Technology 

Department of Mechanical 

Dissertation 

ACADEMIC MASTER 

Domain: Science and Technology 

Division: Mechanical Department 

Specialty: Electromechanics  

Presented by: 

1. Yahia Dou      

2. Saned Ayadi 

3. Saad Eddine Lachheb 

Entitled: 

 

 

 

Dissertation Submitted in Partial Fulfillment of the Requirements for the Master  

Degree in Master 

Publicly defended in: 28 / 05 / 2023 

 

Board of Examiners: 

Dr. Largout Solaf Chairman 

Pr. Beggat Feteh Supervisor 

Dr. Miloudi Khaled Examiner 

Academic Year: 2025/2024  

Techno-Economic Analysis of Photovoltaic Systems Integrated 

with Geothermal Energy for Poultry Housing in El Oued 

Climate Conditions 



 

 

Abstract 

 

This study investigates the integration of renewable energy technologies, particularly 

geothermal and solar energy, into poultry housing systems in arid regions, with a focus on El Oued, 

Algeria. The research aims to develop and assess a geothermal HVAC system tailored for broiler 

chicken farms, promoting energy efficiency, improved animal welfare, and economic viability. A 

comprehensive review of poultry housing requirements, thermal comfort, ventilation strategies, 

and environmental stressors—such as heat stress—was conducted. The study compares traditional 

and modern poultry systems, emphasizing the advantages of hybrid renewable energy systems 

(HRES) combining solar photovoltaic and geothermal energy. The system design includes 

photovoltaic sizing, geothermal heat pump implementation, and ventilation optimization. Field 

data from local poultry farms inform the analysis, revealing substantial performance gains, reduced 

mortality, and enhanced productivity in modern facilities. Results suggest that adopting HRES in 

poultry farming can significantly reduce reliance on fossil fuels, lower operational costs, and 

contribute to sustainable agriculture in desert climates. 

  



 

 

 الملخص

تتناول هذه الدراسة دمج تقنيات الطاقة المتجددة، وخصوصًا الطاقة الحرارية الجوفية والطاقة الشمسية، 

في أنظمة إسكان الدواجن في المناطق الجافة، مع التركيز على منطقة الوادي في الجزائر. يهدف البحث إلى 

ة الجوفية ومخصص لمزارع دجاج ، وذلك يعمل بالطاق (HVAC) تطوير وتقييم نظام تدفئة وتهوية وتكييف

، وزيادة الجدوى الاقتصادية. تم إجراء مراجعة شاملة جودة الدواجن لتعزيز كفاءة استخدام الطاقة، وتحسين 

والعوامل البيئية الضاغطة مثل الإجهاد الحراري. كما تم إجراء  ن الدواجن، استراتيجيات التهويةلمتطلبات إسكا

 التقليدية والحديثة في تربية الدواجن، مع إبراز مزايا أنظمة الطاقة المتجددة الهجينةمقارنة بين الأنظمة 

(HRES)  التي تجمع بين الطاقة الشمسية الكهروضوئية والطاقة الجوفية. يشمل تصميم النظام تحديد حجم

ات ميدانية من الألواح الشمسية، وتطبيق مضخة حرارية جوفية، وتحسين نظام التهوية. وقد استخُدمت بيان

مزارع دواجن محلية في التحليل، مما أظهر تحسناً كبيرًا في الأداء، وانخفاضًا في معدل النفوق، وزيادة في 

الإنتاجية في المنشآت الحديثة. وتشير النتائج إلى أن اعتماد أنظمة الطاقة المتجددة الهجينة في تربية الدواجن 

ويساهم في الزراعة المستدامة في المناخات  حفوري، ى الوقود الأيمكن أن يقلل بشكل كبير من الاعتماد عل

 الصحراوية

.  



 

 

DEDICATION 

 

I dedicate this modest work to my mother and father, symbols of love and affection, who 

sacrificed all their time for my happiness and success, and I hope that they will find here a testimony 

of my deep gratitude. 

I also extend my love to all my family members, my uncles and aunts, my brothers and sisters, 

who supported me throughout my studies, and to all my friends and colleagues, and to all those I 

love. 

  



 

 

Thanks, and Appreciation 

All praise and gratitude are due to Almighty God, whose boundless mercy and guidance have 

empowered us to successfully complete this academic journey. 

We extend our deepest thanks and sincere appreciation to our respected supervisor, Professor 

Beggat Feteh, for his exceptional guidance, valuable insights, and continuous support throughout 

every stage of this thesis. His constructive advice and encouragement have been instrumental in 

shaping the quality and direction of our research. 

We are also profoundly grateful to all those who contributed to the completion of this work, 

particularly the faculty members of the University of El Oued, Department of Mechanical 

Engineering, whose dedication and knowledge greatly enriched our academic experience. 

To all who supported us, both directly and indirectly, we offer our heartfelt appreciation. 

  



 

TABLE OF CONTENTS 

 

 

LIST OF FIGURES ................................................................................................................ I 

LIST OF TABLES ............................................................................................................... IV 

LIST OF ABBREVIATIONS ............................................................................................... V 

GENERAL INTRODUCTION: ................................................................................................... 1 

CHAPTER 01 .......................................................................................................................... 1 

I.1 INTRODUCTION : .............................................................................................................. 3 

I.2 POULTRY HOUSES : .......................................................................................................... 4 

I.3 POULTRY BIRDS AND THEIR THERMOREGULATORY MECHANISM: ................................ 5 

I.4 HEAT STRESS IN CHICKEN : ............................................................................................. 7 

I.5 EFFECTS OF INTERNAL CLIMATE CONDITIONS ON CHICKEN : ....................................... 8 

I.5.1 Temperature : ......................................................................................................... 9 

I.5.2 Relative humidity : ............................................................................................... 10 

I.5.3 Air composition : .................................................................................................. 10 

I.5.4 Air velocity : .......................................................................................................... 12 

I.5.5 Lighting: ................................................................................................................ 12 

I.6 POULTRY HOUSING SYSTEM : ........................................................................................ 13 

I.6.1 Naturally ventilated open housing system : ....................................................... 14 

I.6.2 Building orientation : ........................................................................................... 14 

I.6.3 House width, length and height : ......................................................................... 15 

I.6.4 Roof slope: ............................................................................................................. 16 

I.6.5 Roof overhang: ...................................................................................................... 16 

I.6.6 Ridge opening: ...................................................................................................... 16 

I.6.7 Sidewall openings: ................................................................................................ 16 

I.6.8 Building obstruction: ............................................................................................ 17 

I.6.9 Roof, end-wall and sidewall insulation : ............................................................. 18 



 

I.6.10 Cooling system : .................................................................................................. 18 

I.6.11 Vegetation : ......................................................................................................... 18 

I.7 OPEN HOUSING SYSTEM WITH MECHANICAL VENTILATION : ...................................... 19 

I.7.1 Building a poultry houses : .................................................................................. 19 

I.7.2 Exchange of air : ................................................................................................... 21 

I.7.3 Air inlet system : ................................................................................................... 22 

I.7.4 Types of inlet ventilation system : ....................................................................... 23 

I.7.4.1 Cross ventilation : .............................................................................................. 23 

I.7.5 Air movement inlet ventilated house : ................................................................ 24 

I.7.6 Tunnel ventilation system : .................................................................................. 25 

I.7.7 Poultry exhaust fans : ........................................................................................... 28 

I.8 CONCLUSIONS : ............................................................................................................. 29 

CHAPTER 02 .......................................................................................................................... 1 

II.1 INTRODUCTION : .......................................................................................................... 30 

II.2 POULTRY PRODUCTION IN ALGERIA : ......................................................................... 31 

II.3 GEOTHERMAL ENERGY ............................................................................................... 32 

II.3.1 Working principle of geothermal energy: ........................................................ 33 

II.3.2 The main components of a geothermal energy system : .................................. 34 

II.4 VENTILATION PRINCIPLES : .............................................................................. 36 

II.4.1 Economic importance of ventilation : ............................................................... 36 

II.4.2 Air quality : ......................................................................................................... 37 

II.4.3 Natural ventilation : ............................................................................................ 37 

II.4.4 Electric ventilation : ............................................................................................ 38 

II.5 THE MAIN FACTORS AND INGREDIENTS IN RAISING CHICKENS : ................................ 38 

II.5.1 temperature : ....................................................................................................... 38 

II.6.2 Humidity and litter : ........................................................................................... 39 

II.5.3 Lighting : .............................................................................................................. 41 

II.5.4 Heating equipment:............................................................................................. 42 

II.6 THE IDENTIFICATION OF TRADITIONAL AND MODERN POULTRY FARMERS : ............ 42 

II.6.1 The location of the poultry house where the study was carried out : ............ 43 



 

II.6.2 Breeders ages in Oued Souf : ............................................................................. 44 

II.7 POULTRY BUILDING CHARACTERISTICS ..................................................................... 45 

II.7.1 Capacity of buildings: ......................................................................................... 46 

II.7.2 Chick density per  : ............................................................................................. 46 

II.7.4 The number of chicks in buildings : .................................................................. 47 

II.8 BUILDING EQUIPMENT AND MATERIALS : ................................................................... 48 

II.8.1 Type of drinkers : ................................................................................................ 48 

II.8.2 Type of feeders : .................................................................................................. 48 

II.8.3 Type of heating : .................................................................................................. 49 

II.8.4 Starting temperature : ........................................................................................ 49 

II.8.5 Warm-up time : ................................................................................................... 50 

II.8.6 The period of light : ............................................................................................ 50 

II.8.7 Type of ventilation : ............................................................................................ 50 

II.8.8 Number of mortalities in batch : ....................................................................... 51 

II.8.9 Weight of each day 1 chick : .............................................................................. 51 

II.8.10 First week chick weight : .................................................................................. 52 

II.8.11 Weight of each chick of the 2nd week : ........................................................... 52 

II.8.12 Weight of each chick in the 3rd week : ........................................................... 53 

II.9 ANALYSIS AND DISCUSSION : ....................................................................................... 54 

II.10 CONCLUSION : ............................................................................................................ 55 

CHAPITRE III : .................................................................................................................... 29 

III.1. INTRODUCTION: ........................................................................................................ 56 

III.2. DIMENSION OF THE PHOTOVOLTAIC INSTALLATION INSTALLED AT THE BASE: ..... 56 

III.2.1. Determine an energy level: .............................................................................. 56 

III.2.2. Study of the Inclination and Orientation of the Panels: ............................... 57 

III.2.3. Sizing of photovoltaic modules: ....................................................................... 59 

CHAPITRE IV : .................................................................................................................... 54 

IV.1. INTRODUCTION .......................................................................................................... 69 

IV.2 TECHNICAL AND ECONOMIC TABLES FOR PV SYSTEMS ............................................ 69 

IV.3 INSTALLATION AND MAINTENANCE ........................................................................... 70 



 

IV.4 MECHANICAL AND ELECTRICAL INSTALLATION ....................................................... 70 

IV.4.1. INSTALLATION OF THE PV GENERATOR ............................................ 70 

IV.5. MAINTENANCE .......................................................................................................... 72 

IV.5.1. Modules .............................................................................................................. 72 

IV.5.2. Batteries ............................................................................................................. 72 

IV.5.3. Regulators .......................................................................................................... 72 

IV.7. CONCLUSION ............................................................................................................. 73 

GENERAL CONCLUSION ................................................................................................. 74 

REFERENCE .......................................................................................................................... I 

 



I 

 

 

LIST OF FIGURES 

 

 

Figure I. 1: poultry houses [12]. ......................................................................................... 4 

Figure I. 2: Poultry thermoregulation mechanism. ............................................................ 5 

Figure I. 3: thermoregulation. ............................................................................................ 6 

Figure I. 4: Heat stress in chicken. ..................................................................................... 8 

Figure I. 5: Air installation in poultry houses. ................................................................. 11 

Figure I. 6: poultry house lighting. .................................................................................. 13 

Figure I. 7: An illustration of the broiler poultry house. .................................................. 14 

Figure I. 8: Dimensions and location of the poultry house building[5]. .......................... 15 

Figure I. 9: Poultry sidewall inlets - wall vent poultry house ventilation. ....................... 17 

Figure I. 10: Building poultry houses[65]. ....................................................................... 20 

Figure I. 11: Negative-pressure air intake pipes[2].......................................................... 22 

Figure I. 12: Air inlet control in poultry houses. ............................................................. 23 

Figure I. 13: Overhead ventilation in poultry house. ....................................................... 24 

Figure I. 14:Air movement inside the poultry house. ...................................................... 25 

 

Figure II. 1: Evolution of white meat production in the last decade[69]. ........................ 32 

Figure II. 2: Geothermal energy. ..................................................................................... 32 

Figure II. 3: Schematic diagram of the geothermal heat pump (GHP) system for the broiler house 

[103]. ......................................................................................................................... 33 

Figure II. 4: open loop system[101]. ............................................................................... 35 

Figure II. 5: spiral closed loop system [80]. .................................................................... 35 

Figure II. 6: Ventilation in poultry houses. ...................................................................... 36 

Figure II. 7: Ventilation Natural. ..................................................................................... 38 

Figure II. 8: Electric ventilation. ...................................................................................... 38 



II 

 

Figure II. 9: Wood carpentry in the poultry house. ......................................................... 40 

Figure II. 10: Types of light sources that can be used for broilers. .................................. 41 

Figure II. 11 : Electric chicken heater. ............................................................................ 42 

Figure II. 12: traditional and modern poultry farmers. .................................................... 43 

Figure II. 13: Location of El-Oued Province in Algeria. ................................................. 44 

Figure II. 14 : (A) Traditional poultry farmers. - (B) Modern poultry farmers. .............. 44 

Figure II. 15 : (A) Traditional poultry farmers - (B) modern poultry farmers. ............... 45 

Figure II. 16 : (A) Type of traditional building - (B) Type of modern building.............. 45 

Figure II. 17: Capacity of buildings (traditional, modern). ............................................. 46 

Figure II. 18 : (A): Chick density / 𝑚2 traditional – (B): Chick density /𝑚2 modern. ... 46 

Figure II. 19 : Surface area of traditional and modern buildings. .................................... 47 

Figure II. 20: Number of chicks in buildings (traditional and modern). ......................... 47 

Figure II. 21: (A) Type traditional drinkers.- (B) Type modern drinkers. ....................... 48 

Figure II. 22 : (A) Traditional feeder type. - (B) Modern feeder type. ............................ 48 

Figure II. 23 : (A) Type of traditional heating - (B) :Type of modern heating. .............. 49 

Figure II. 24 : Starting temperature of traditional and modern buildings. ....................... 49 

Figure II. 25 : (A) Traditional heating time. - (B) Modern heating time. ........................ 50 

Figure II. 26 : (A) Type of traditional ventilation - (B) Type of modern ventilation ...... 50 

Figure II. 27:Number of deaths in batch arrivals (traditional, modern). ......................... 51 

Figure II. 28: Weight of each day 1 chick (traditional, modern). .................................... 51 

Figure II. 29: Weight of each chick in the 1st week (traditional, modern). ..................... 52 

Figure II. 30 : Measuring chick weight 1st week. ........................................................... 52 

Figure II. 31 : Weight of each chick of the 2nd week (traditional, modern). .................. 52 

Figure II. 32 : Measuring chick weight 2nd week. .......................................................... 53 

Figure II. 33 : Weight of each chick of the 2nd week (traditional, modern). .................. 53 

 

Figure III. 1: Calculation of the slope by PVGIS[110]. .................................................. 58 

Figure III. 2: Result of tilt visualization in PVGIS. ........................................................ 58 

Figure III. 3: Polycrystalline solar panel ......................................................................... 60 

Figure III. 4: Rosefinch MPPT regulator ........................................................................ 63 



III 

 

Figure III. 5: Inverter 40KW solar charger ..................................................................... 64 

Figure III. 6: Lithium battery ........................................................................................... 65 

Figure III. 7: heat pump (ghp) ......................................................................................... 66 

Figure III. 8: modelling a cable. ...................................................................................... 67 

  



IV 

 

LIST OF TABLES 

 

 

Table I. 1: Recommanded température Schedule. ............................................................. 9 

Table I. 2: Common gas levels in poultry houses. ........................................................... 11 

Table I. 3: Air velocity recommendations for tunnel-ventilated dwellings. ..................... 25 

 

Table II. 1: represents the optimum temperature for broiler chickens. ............................ 39 

Table II. 2: represents the optimum humidity for broiler chickens. ................................. 40 

Table II. 3: Lighting Program Recommendations. .......................................................... 42 

 

Table III. 1: Energy requirements of a joinery workshop ............................................... 57 

Table III. 2: Solar irradiation in El oued (source: PVGIS). ............................................. 59 

Table III. 3: System voltages corresponding to each peak power interval. ..................... 60 

Table III. 4: Characteristics of polycrystalline solar panels ............................................ 61 

Table III. 5: Characteristics of MPPT solar controllers ................................................... 63 

Table III. 6: Characteristics of solar inverter ................................................................... 64 

Table III. 7: Characteristics of Lithium battery ............................................................... 65 

Table III. 8: Characteristics of heat pump (ghp) .............................................................. 66 

 

Table IV. 1: Technical and economic study of a PV system ........................................... 69 

 

   



V 

 

List of abbreviations 

 

HVAC: Heating Ventilation and Air Conditioning. 

IEA: International Energy Agency. 

HRES:  Hybrid Renewable Energy Systems. 

PV/T: photovoltaic/thermal. 

EAHE: Earth Air Heat Exchangers. 

WTO: World Trade Organization.



 

General Introduction: 
 



General Introduction 

 

1 

 

General Introduction: 

The globe has experienced an intensification of global environmental concerns since the end 

of the twentieth century and the beginning of the twenty-first century, arguably the most notable 

of which is the phenomenon of global warming and climate change. Many publications point to 

the significance of traditional energy sources (fossil fuels) in these alarming statistics, which 

anticipate the worst if no structural changes to the energy paradigm are made, particularly in 

developing nations [1]. 

Renewable energy sources, including wind, solar, and hydrogen power, are better for the 

future. Among these, geothermal energy extracted from the Earth’s internal heat stands out for its 

capacity to operate independently of weather conditions and deliver consistent, 24-hour energy. It 

is utilized for various applications, including heating, cooling, bathing, and medicinal purposes. 

With suitable infrastructure, geothermal power can compete economically with conventional 

energy sources such as coal and natural gas. By reducing reliance on fuel imports and enhancing 

national energy security, geothermal energy presents a viable alternative. Additionally, it is 

ecologically sustainable and globally accessible, making it a key component in the renewable 

energy transition [1]. 

Renewable energy is derived from natural sources that replenish on a human timescale; 

examples include sunlight, wind, rain, tides, waves, and geothermal heat [1]. In contrast to fossil 

fuels, which are depleted much faster than they can be replenished, most renewable sources are 

replenished rapidly. However, not all renewable energy sources are automatically sustainable; for 

example, specific biomass resources become unsustainable under current usage patterns [2][3]. 

Geothermal HVAC (Heating, Ventilation, and Air Conditioning) is a technology that harnesses 

geothermal energy for climate control. It functions by transferring the Earth’s stable subsurface 

temperature into indoor environments, using components such as a ground-source heat pump and 

an underground heat exchanger (loop system). This method allows efficient heating and cooling of 

buildings, including homes, greenhouses, and animal shelters [4]. 

In this research, we address a practical application of geothermal energy: the development of 

a geothermal heating, ventilation, and air conditioning (HVAC) system specifically designed for 

poultry houses. The goal is to ensure an ideal, uniform distribution of heat, ventilation, and air 



General Introduction 

 

2 

 

conditioning at a lower cost, particularly suited for arid regions where climate extremes challenge 

poultry productivity. This system promises to enhance energy efficiency, improve animal welfare, 

and increase economic returns for poultry farmers [4]. 

The objective of our work is to study the heating, ventilation, and air conditioning system 

powered by geothermal energy and evaluate its integration in poultry farms located in arid areas. 

This will be presented in four main chapters: 

 Chapter One: A literature review on broiler chickens and their housing systems, including 

breeding regimens, operational techniques, and planned interventions. 

 Chapter Two: A detailed estimation of broiler chickens’ environmental needs—including 

temperature, ventilation, and lighting—throughout their lifecycle and across seasons. 

 Chapter Three: A technical exploration of poultry house construction characteristics, such 

as geometry, material choices, insulation, and design features impacting thermal 

performance. 

 Chapter Four: Analysis of the energy-consuming equipment used in poultry facilities (type, 

power, efficiency, and placement) along with a study of thermal and air quality demands to 

ensure optimal poultry house operation.



 

 

Chapter 01 

Literature review on 

Broilers and its housing 



Literature review on Broilers and its housing 

 

3 

 

I.1 Introduction : 

According to the International Energy Agency (IEA), fossil fuels account for 81% of the 

world's primary energy consumption. Although these resources are depleting rapidly, their use has 

surged due to technological advancements, leading to serious environmental consequences such as 

acid rain and global warming [4]. In response, many developed and developing nations are adopting 

sustainable solutions to enhance energy efficiency in buildings. However, despite the global 

availability of renewable energy sources, the poultry industry still heavily depends on fossil fuels 

for heating and cooling needs [6]. The integration of Hybrid Renewable Energy Systems (HRES), 

particularly those combining solar and geothermal energy, presents a promising path toward 

reducing this dependency by leveraging complementary energy profiles for year-round efficiency. 

In poultry farming, maintaining optimal moisture levels and appropriate litter conditions is 

essential for the health and welfare of chickens [5]. One of the most critical environmental 

challenges faced by poultry producers is heat stress, especially during the summer months. If a 

bird's body temperature exceeds its normal level of 41°C by more than 4°C, it can lead to fatalities 

[6] [7]. This stress significantly impacts broiler production, causing substantial energy and financial 

losses within the livestock sector. For instance, in the United States alone, heat stress in poultry 

houses is estimated to result in annual losses ranging from $127.3 million to $164.6 million, 

representing approximately 7.0% to 7.5% of total sector losses [8] [9]. The implementation of 

HRES could alleviate heat-related energy burdens by providing reliable, renewable heating and 

cooling solutions, especially in off-grid or rural farming areas. 

To safeguard poultry health, breeders must adopt appropriate management strategies. The 

thermoneutral zone the optimal temperature range for chickens varies with age, as shown in Figure 

1 [6]. While European regulations provide guidelines for bird density, they often overlook broader 

welfare considerations within poultry housing [8]. In colder climates, standard ventilation systems 

typically operate on timer-controlled minimum ventilation, with airflow speeds around 0.5 m/s [10] 

[11]. Coupling geothermal systems for stable subsurface temperature exchange with solar energy 

for peak daytime loads can ensure more consistent indoor conditions, reduce over-reliance on 

mechanical systems, and cut down operational costs. 



Literature review on Broilers and its housing 

 

4 

 

Meanwhile, poultry farming in Algeria, particularly in the El-Oued region, continues to face 

challenges in providing adequate environmental conditions. Many breeders still depend on 

conventional methods such as fossil fuels and gas for heating, ventilation, air conditioning, and 

lighting, highlighting the need for modernized and sustainable practices. The adoption of HRES 

tailored to local climatic conditions such as high solar irradiance and accessible geothermal 

gradients can offer Algerian poultry farms a viable path to improving energy efficiency, reducing 

emissions, and enhancing animal welfare through more stable and environmentally friendly 

microclimates. 

I.2 poultry houses : 

The design of poultry housing plays a vital role in shaping the indoor climate, which directly 

affects the birds' health, growth, and productivity. Consequently, the choice of a chicken housing 

system for a poultry farm is largely influenced by the region’s prevailing climatic conditions. In 

tropical regions, the open poultry house system is often preferred due to its simple construction, 

effective natural heat regulation, and low operational costs. In contrast, controlled poultry house 

systems are more commonly used in temperate climates, where maintaining consistent indoor 

conditions is essential [12] [13] [14]. 

 

Figure I. 1: poultry houses [12]. 

  



Literature review on Broilers and its housing 

 

5 

 

I.3 Poultry birds and their thermoregulatory mechanism: 

Birds are feathered, oviparous animals with a high metabolic rate and typically breathe at a 

rate of 40 to 50 breaths per minute [15]. Their average internal body temperature ranges between 

39°C and 42.2°C [16] [17] [18]. During hot weather, poultry birds regulate their body temperature 

and maintain thermal balance primarily through heat loss mechanisms such as conduction, 

convection, radiation, and evaporative cooling [5] [19] [20]. 

 

Figure I. 2: Poultry thermoregulation mechanism. 

Sensible heat loss through convection, radiation, and conduction is most effective when the 

ambient temperature is at or below the bird's thermoneutral zone. Within this zone, approximately 

60% of the heat dissipated during body temperature regulation occurs through evaporative cooling 

[5]. Sensible heat is primarily lost through exposed areas such as the wattles, shanks, and other 

featherless regions around the neck and wings [21]. This form of heat loss does not impact the 

bird's behavior, feed intake, or metabolism [22]. The effectiveness of sensible heat loss depends on 

the temperature difference between the bird’s body and its surrounding environment. 



Literature review on Broilers and its housing 

 

6 

 

When ambient temperatures exceed 24°C, evaporative cooling—or latent heat loss—becomes 

the main method of heat dissipation for birds of all ages [21]. At temperatures above the 

thermoneutral zone, birds rely on panting to lose heat through evaporation from their respiratory 

tract. However, this process diverts energy away from growth and development. Prolonged panting 

can also lead to dehydration and respiratory alkalosis, caused by a decrease in blood pH from 

excessive carbon dioxide loss and inadequate water intake [21]. High humidity levels can further 

complicate evaporative cooling, as water does not evaporate as efficiently. This poses a challenge 

in humid climates, where poultry producers often rely on evaporative cooling systems to manage 

heat during the summer months [5]. 

 

Figure I. 3: thermoregulation. 

Increasing the volume and speed of airflow over birds enhances heat loss through convection, 

helps remove heat accumulated inside the poultry house, and reduces the negative impact of high 

humidity on evaporative cooling [5]. In a study by Simmons et al. [23], 3 week old male broilers 

were exposed to a cyclic temperature range of 25–30–25°C in a controlled environment over a four 



Literature review on Broilers and its housing 

 

7 

 

week period, with varying wind speeds: still air (0.25 m/s), 2 m/s, and 3 m/s. The results showed 

that higher airspeeds positively affected the growth and development of older birds. 

Water is a crucial resource in poultry production, not only for its mineral content but also for 

its impact on feed intake [24]. Modern poultry operations have largely replaced traditional open 

watering systems with nipple drinkers, which provide cleaner water, reduce spillage, and minimize 

the labor required for maintenance. In a study by May et al. [25], chickens raised with open water 

systems consumed more water than those with nipple drinkers. However, when raised under 

controlled conditions with air velocities of 0.25 and 2.1 m/s, birds using nipple drinkers achieved 

higher weight gain and better feed conversion rates compared to those using open water systems 

[26]. Therefore, maintaining proper ventilation in poultry houses is essential, as it enables birds to 

regulate their body temperature effectively through sensible heat loss. 

I.4 Heat stress in chicken : 

Heat stress is a widespread issue in the poultry industry, especially in meat and egg 

production. Chickens begin to experience heat stress when the ambient temperature reaches or 

exceeds 26.7°C. At this point, they start panting, which can negatively affect their optimal growth 

rate, hatching success, egg size, eggshell quality, and overall egg production. The situation worsens 

when high humidity accompanies elevated temperatures. Heat stress has been associated with 

reduced comfort, slower growth rates, poorer feed conversion, and lower live weight gain in 

broilers [21]. 



Literature review on Broilers and its housing 

 

8 

 

 

Figure I. 4: Heat stress in chicken. 

Acute heat stress occurs when birds are exposed to high temperatures for a short duration, 

while chronic heat stress results from prolonged exposure to elevated temperatures. Birds raised in 

open-sided shelters commonly used in tropical regions are particularly susceptible to chronic heat 

stress. This prolonged exposure has been shown to adversely affect growth and production 

efficiency, egg and meat quality, embryonic development, reproductive performance, immune 

function, and the incidence of disease in broilers, laying hens, and breeders [21, 27, 28, 29, 30, 31]. 

I.5 Effects of internal climate conditions on chicken : 

Understanding the influence of indoor climatic conditions in a poultry house on bird behavior 

and responses is essential, as it directly affects heat management in poultry production. This 

knowledge is crucial for informing the architectural design of open air poultry houses aimed at 

reducing heat stress and ensuring optimal productivity, particularly in arid regions. Key climatic 

factors to consider include temperature, relative humidity, air composition, airflow speed, and 

lighting conditions. 

  



Literature review on Broilers and its housing 

 

9 

 

I.5.1 Temperature : 

The optimal temperature range for different classes and age groups of chickens to achieve 

maximum performance is a topic of debate. This is likely influenced by other environmental factors 

such as humidity and wind speed, which can affect temperature fluctuations and the birds' 

responses to previous climate conditions. Chickens, regardless of their breed or age (broiler, pullet, 

or breeder), can tolerate a wide range of temperatures. However, exposure to high temperatures has 

been shown to decrease their production performance [17], and this effect can be intensified by 

higher relative humidity, which hampers evaporative cooling [32]. 

For day-old chicks, Ketelaars [16] recommended a temperature of 30–32°C at the bird's level. 

As shown in Table I.1, the temperature should be gradually lowered by 3–4°C until the chicks 

reach 4 weeks of age. Growing broilers, according to Daghir [19], thrive within a temperature range 

of 18–22°C. Holik [15] noted in earlier studies that birds are most comfortable when temperatures 

range between 18 and 24°C. However, the best performance in poultry production is ultimately 

determined by the market value of the product in relation to feeding costs. 

The table below (Table 1) presents the recommended temperatures for poultry farming in the 

El-Oued region. 

Table I. 1: Recommended temperature Schedule. 

Age of chicken (week) Température range (°C) 

1 30-32 

2 30-26 

3 26-23 

4 23-20 

5 20 

Maintaining the optimal production temperature in tropical regions is challenging, so it is 

essential for poultry house designers to carefully consider temperature fluctuations. 

  



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I.5.2 Relative humidity : 

According to Oloyo [17], when internal temperatures exceed 26.7°C combined with high 

relative humidity, it significantly reduces feed efficiency, feather quality, pigmentation, and weight 

gain in chickens. Additionally, regardless of changes in relative humidity, the birds' performance 

was poor when internal temperatures ranged between 35°C and 37.8°C. This suggests that lower 

temperatures, along with higher humidity, may improve bird performance. However, humidity 

must be carefully managed, as it can create a conducive environment for microbes, increasing the 

risk of illness among the birds [18, 33]. 

Temperature and relative humidity are closely related. During the brooding period, especially 

in the early weeks, internal relative humidity may be low or excessively low due to the heat required 

for the chicks at that age or because they are thirsty or hatched in warmer conditions. As the chicks 

grow, the water vapor released during their evaporative cooling process to regulate body 

temperature causes internal relative humidity to rise rapidly [16]. Therefore, the third week and 

beyond are critical stages in chicken production, regardless of bird class. 

Oloyo [17] also found that laying hens require relative humidity levels of 60–80% during the 

brooding phase and 50–70% after brooding for optimal performance. 

I.5.3 Air composition : 

The decomposition of bird feces generates harmful gases such as ammonia, carbon dioxide, 

methane, and hydrogen sulfide, which are detrimental to the health and performance of birds, the 

condition of cages, and the overall environment [16, 18, 34, 35, 36, 37, 38]. These gases are 

particularly concerning due to their negative effects. For optimal chicken production, it is 

recommended that ammonia concentrations should not exceed 25 ppm, and carbon dioxide levels 

should be kept below 2500 ppm [18, 39]. Regular removal of fecal waste from the poultry house 

is essential to reduce gas emissions and maintain the health and well being of the birds [17]. 



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Figure I. 5: Air installation in poultry houses. 

In an enclosed poultry house, the air composition can become hazardous if it is not regularly 

refreshed. Without proper ventilation, gases such as carbon dioxide, ammonia, and other harmful 

substances can reach dangerously high concentrations. Table I.2 outlines the critical and ideal 

levels of various gases as identified by research. The ventilation system plays a key role in 

exchanging the air within the building, supplying the oxygen necessary for the birds' survival and 

removing the toxic gases and odors produced by respiration and waste decomposition. 

Additionally, the ventilation system helps dilute airborne pathogens, keeping them at safe levels 

for the birds' health. 

Table I. 2: Common gas levels in poultry houses. 

Gaz Symbol Lethal Desirable 

Carbon Dioxide CO2 Above 30% Below 1% 

Methane CH4 Above 5% Below 1% 

Ammonia NH3 Above 500ppm Below 40ppm 

Hydrogen Sulfide H2S Above 500ppm Below 40ppm 

Oxygen O2 Below 6% Above 16% 



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Ventilation is essential for removing excess moisture from the poultry house. Effective 

ventilation reduces relative humidity, promotes better health, and prevents moisture buildup on 

walls and ceilings. As air is heated, its volume increases, enabling it to hold more moisture. For 

instance, when the air temperature rises by approximately 20°F, the moisture-holding capacity of 

the air doubles. 

I.5.4 Air velocity : 

Variable air velocity within the poultry house can help reduce high indoor temperatures to 

some degree. Additionally, air velocity plays a crucial role in convection cooling and maintaining 

air quality [5, 18]. In hot climates, it is recommended that the ventilation capacity be at least 5m³ 

per chicken per hour, with inlets providing an average of 1.5cm² per m³ of ventilation [16]. 

Hulzebosch [18] suggests that in temperatures ranging from 25 to 30°C, air velocity can be kept at 

0.1–0.2 m/s. However, under the same temperature conditions, Lacy and Czarick [40] observed 

that broilers grew faster at air velocities of 2 and 3 m/s, respectively. 

The effects of air velocity on chickens were further explored by considering their age within 

the temperature range of 25–30°C with varying air velocities. The research showed that increased 

air velocity (2 and 3 m/s) benefited 6-week-old broilers more than 4-week-old broilers. This could 

be attributed to the higher heat requirements of younger birds during the brooding period. 

I.5.5 Lighting: 

Lighting during the early stages of a bird's life has minimal to no effect on their hormonal 

system; its primary role is to stimulate activity, including feeding, growth, and both physical and 

physiological functions [15, 41, 42].  

However, increasing the duration and intensity of light exposure can lead to negative outcomes 

such as fatigue, cannibalism, immune responses, limb deformities, and even death [41, 43, 44, 45, 

46, 47]. 



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A commonly used lighting schedule involves 16 hours of light followed by 8 hours of darkness, 

which has been shown to enhance overall poultry performance [15, 48, 49, 50]. Additionally, 

intermittent lighting—alternating short periods of light and darkness—has also demonstrated 

benefits in improving bird productivity [16, 51, 52, 53, 54]. During the post-hatch period (1–7 days 

old), a continuous lighting program with a minimum intensity of 20 lux is recommended to help 

chicks acclimate to their environment and encourage feeding [41]. After this stage, the light 

intensity is reduced to 3–5 lux, and an intermittent lighting system is introduced to better manage 

the birds’ activity, thereby supporting improved performance and production [16, 41]. 

 

Figure I. 6: poultry house lighting. 

Birds raised under yellow, green, and blue light sources tend to achieve higher body weights 

compared to those grown under red and orange light sources [55, 56, 57]. In their review, Lewis 

and Morris [55] observed that birds exposed to blue light were generally calmer, while those reared 

under red light displayed more active and aggressive behavior. Additionally, red light was shown 

to enhance sexual activity in birds. 

I.6 Poultry housing system : 

The type of poultry housing system used in chicken production plays a vital role and cannot 

be overstated. It protects the birds from extreme environmental conditions that could negatively 

impact their health and productivity. The total heat generated inside a poultry house comes from 

the birds themselves, the surrounding environment, and the decomposition of fecal matter [58, 59, 

60].  



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Therefore, the choice of housing system is a key factor influencing the management approach 

used on the farm. In tropical regions, two common types of housing systems are the naturally 

ventilated open system and the mechanically ventilated open system, both of which are explored. 

 

Figure I. 7: An illustration of the broiler poultry house. 

I.6.1 Naturally ventilated open housing system : 

The open poultry housing system is commonly used in tropical regions due to its simplicity, 

cost-effectiveness, and the ease with which heat can be regulated through natural ventilation [5, 

32, 61]. However, this type of housing is susceptible to pests such as insects, rodents, wild birds, 

and other small predators, all of which can negatively affect the welfare, productivity, and 

performance of the chickens. To address these challenges, dwarf sidewalls are extended up to the 

roof eaves and covered with corrugated wire mesh to keep predators out. Additionally, a pesticide-

filled gutter is often installed around the perimeter of the house to deter insect infestations. Key 

design considerations for optimizing performance and productivity in open poultry housing are 

outlined below. 

I.6.2 Building orientation : 

To minimize sidewall exposure to direct sunlight, poultry houses should be oriented in an east-

west direction [5, 60]. This is important because direct solar radiation can intensify heat stress in 



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birds. While the deep litter system allows chickens to avoid direct sunlight, it can also cause them 

to cluster in specific areas of the house. This crowding can hinder effective cooling, potentially 

leading to stampedes or even fatalities [5]. 

I.6.3 House width, length and height : 

While an east-west orientation helps reduce exposure to direct sunlight, it can also limit the 

advantages of prevailing east or west winds. To address this, Daghir [5] recommended that the 

width of the poultry house should not exceed 12 meters. This helps maintain a balanced air 

exchange rate and consistent temperature throughout the building. 

 

Figure I. 8: Dimensions and location of the poultry house building[5]. 

Moreover, the poultry house design should accommodate the routine activities and services 

carried out by farmers and professionals, such as bird transfer, feeding, beak trimming, waste 

disposal, and vaccination. When these tasks are performed manually, maintaining a long poultry 

house can become challenging. To enhance movement and service efficiency, doors should be 

installed every 15–30 meters [119]. According to Qureshi [32], in the case of battery cages, it is 

essential to consider the number of tiers being implemented. A two tier cage system allows for 

better air circulation within the building, while three and four tier systems may hinder airflow. As 

such, it is recommended that cage rows be limited to three, with central aisles no narrower than 1.2 

meters and at least a 1 meter clearance between the top tier and the ceiling[120]. 



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I.6.4 Roof slope: 

A roof slope of 45 degrees is recommended as it helps minimize heat absorption from direct 

sunlight, increases the distance between the birds and the heat trapped beneath the roof, and 

facilitates rapid release of accumulated heat through a ridge vent. This design also enhances the air 

volume inside the structure, improving ventilation, and creates additional overhead space for 

installing equipment [5, 60, 62]. However, for insulated roofs, the required slope depends on the 

effectiveness of the insulation material used. 

I.6.5 Roof overhang: 

Roof overhangs can serve to shield a building’s sidewalls from both direct and reflected solar 

radiation. The appropriate length of the overhang depends on the height of the sidewalls [2]. When 

correctly positioned at a roof slope of 45° [60], roof overhangs can reduce heat absorption by the 

sidewalls by approximately 30%. 

I.6.6 Ridge opening: 

Hot air naturally rises above cooler air due to differences in air density. Installing ridge vents 

in the poultry house can aid in ventilation by creating a stack effect. To ensure proper airflow and 

prevent inadequate ventilation, it is important to maintain an appropriate distance between 

buildings [2, 61]. However, ridge vents have been found to be less effective in insulated poultry 

houses due to the consistent temperature maintained inside [63]. 

I.6.7 Sidewall openings: 

The sidewall consists of a permeable membrane, such as corrugated wire mesh, combined with 

an adjustable curtain, and is constructed up to the roof eave. A minimum height of 0.4 meters is 

recommended to safeguard the poultry house against water infiltration, direct and indirect sunlight, 

pests, and predators [2]. The corrugated wire mesh facilitates effective ventilation inside and 

outside the structure, while the adjustable curtain regulates airflow and airspeed. Additionally, the 



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curtain can be translucent or come in various colors to support the implementation of intermittent 

lighting systems [5, 15, 63]. 

 

Figure I. 9: Poultry sidewall inlets - wall vent poultry house ventilation. 

I.6.8 Building obstruction: 

Maintaining an adequate distance between buildings is crucial to ensure sufficient air exchange 

rates. Key factors influencing optimal spacing include wind speed, wind direction, and the 

surrounding topography. Nevertheless, the distance between poultry houses can be determined 

using the following equation provided by [63]. 

D= 0.4∗H∗L∗0.5 

Where: 

 D represents the spacing between houses (measured from the ridge of the nearest wall of 

the adjacent building), 

 H is the height of the neighboring structure, and 

 L is the length of the neighboring structure. 

Vegetation around the poultry house should be kept minimal and maintained at an average 

height to reduce the risk of wild bird nesting and the intrusion of rodents and other predators. 

Additionally, tree branches should be trimmed to roof eave level to prevent interference with 

airflow across the house [2]. 



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I.6.9 Roof, end-wall and sidewall insulation : 

In tropical regions, farmers have effectively constructed naturally ventilated poultry houses 

using locally available materials such as thatched roofs and bamboo [32]. For naturally ventilated 

poultry buildings, ceiling insulation should have a minimum thermal resistance (R-value) of 1.25 

m²·°C/W. In areas where temperatures exceed 40°C, an R-value of at least 2.25 m²·°C/W is 

recommended [2]. There are various options for insulating a poultry house ceiling, including drop 

ceilings, rigid board insulation, spray polyurethane foam, and reflective insulation. 

I.6.10 Cooling system : 

Rooftop sprinklers have proven effective in significantly reducing roof temperatures [5, 60]. 

However, the roofing material selected must be capable of withstanding constant exposure to water 

[2]. During hot weather, fogging systems can help enhance evaporative cooling for poultry by 

generating a fine mist under high pressure, which helps keep the birds cool. Still, it's essential to 

regulate the indoor humidity, as excessive moisture combined with high temperatures can 

negatively affect bird health [5, 60]. 

To further mitigate heat stress, circulation fans are used to increase air velocity, enhancing 

convective cooling. Typically, these fans generate air speeds of at least 0.5 m/s and effectively 

ventilate an area equivalent to 15 times their horizontal diameter and 5 times their vertical diameter 

[5]. For best performance, they should be installed 1–1.5 meters above the floor and tilted 

downward at a 5° angle. 

I.6.11 Vegetation : 

Shrubs and grasses contribute to reducing both reflected and direct solar radiation through 

shading and convective cooling [60]. To deter pests and predators, it is important to keep the 

vegetation well maintained and trimmed [2]. Additionally, planting tall trees along the sides of the 

poultry house can create a natural canopy that protects the sidewalls from direct and reflected 

sunlight during the hottest parts of the day. 



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I.7 Open housing system with mechanical ventilation : 

The use of mechanically ventilated housing systems arose from the need to maintain suitable 

indoor environmental conditions for optimal bird performance during extreme weather. 

Mechanical ventilation offers greater control over air exchange, airflow velocity, and direction [2, 

16]. These systems typically operate using either positive or negative pressure. 

The most common type, the negative-pressure system, functions by using fans to expel air 

from the building through a designated air inlet system. This process creates a low-pressure 

environment inside, causing fresh air to enter through the same inlets [2]. 

Negative-pressure systems can be implemented using inlet or tunnel ventilation. Inlet 

ventilation features a uniform distribution of exhaust fans and air inlets throughout the house. In 

contrast, tunnel ventilation places exhaust fans at one end and air inlets at the opposite end, thereby 

enhancing airspeed and promoting more efficient air exchange [2]. 

I.7.1 Building a poultry houses : 

Housing plays a crucial role in poultry farming, and many producers often ask how to properly 

construct a poultry house. Essentially, proper housing is key to maintaining bird health, 

encouraging rapid growth, and maximizing productivity [5]. The structure should be well-insulated 

and securely built to ensure effective ventilation management [2]. 

Instead of solid walls, insulated movable curtains can be used on the sidewalls during colder 

seasons or power outages. However, it's important to note that while movable curtains offer 

flexibility, solid walls generally provide superior insulation. 

The floor of the house should be made of concrete and must be both rat-proof and moisture-

resistant. To further prevent rodent and snake intrusion, the concrete floor should extend about 1.5 

feet beyond the wall on each side. For deep litter systems, doors should open outward and measure 

at least 6 feet by 2.5 feet in size. The image below illustrates the geometric and structural design 

of poultry houses (Figure I.10) [65]. 



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Here are some essential guidelines for constructing an effective poultry housing system: 

 The poultry house must be well ventilated to ensure healthy air circulation. 

 Allow ample sunlight and fresh air to enter the building. 

 Ideally, the house should be oriented from north to south for better exposure and 

temperature regulation. 

 When constructing multiple houses, maintain a spacing of approximately 12 meters 

between each unit. 

 Thoroughly clean the house before introducing the birds. 

 Create a deep litter system and keep it consistently dry and clean. 

 Arrange feed and feeding equipment at appropriate intervals based on the number and needs 

of the birds. 

 It's best to build the poultry house in an open, well aerated area [65]. 

 

Figure I. 10: Building poultry houses[65]. 

  



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I.7.2 Exchange of air : 

The combination of high external temperatures and the heat generated by activities within the 

poultry house increases the temperature of the indoor air. To maintain the indoor temperature 

within 2.8°C of the outdoor air temperature, a properly functioning mechanical ventilation system 

must quickly exchange the air. The following formula can be used to calculate the appropriate size 

of the exhaust fan needed for effective ventilation [2]. 

Building surface heat(w)=  
𝐴

𝑅
  ∗ ( TO – Ti) 

Where: 

 A represents the size of the building surface (m²) 

 R is the insulation value of the wall material (m²·C/W) 

 Outside temperature (°C) refers to the ambient external temperature 

 Inside temperature (°C) is the indoor temperature 

 To is the maximum exterior temperature that is not influenced by external environmental 

factors. 

When calculating heat gain for a roof in a building with attic space, the To value for ceilings 

with insulation directly under the roof is considered to be 65°C [2]. To ensure bird comfort, the Ti 

value should be considered to be 27°C. The cumulative insulation value of the wall segment is 

equal to the R value. 

The total heat produced (both sensible and latent) in commercial broilers is 7.9 W/kg, while 

for broilers, pullets, and broiler breeders, it is 5.1 W/kg [2, 64]. The heat generated by the birds can 

be expressed as shown below [2]. 

Bird heat (w) = sensible heat (W/kg) ∗ weight of the bird (kg) 

50 percent of the total heat produced by birds is sensible heat. 

Total heat (W) =building surface heat (W) +bird heat (W) 

However, the air movement capacity required to maintain a temperature difference of 



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2.8°C between intake and exhaust air is shown below. 

Air capacity (m3/h) =total heat (W) ∗ 3.4/2.8°C 

I.7.3 Air inlet system : 

The extraction of air from the poultry house creates negative air pressure inside, causing fresh 

air to automatically flow in through designated openings. The speed and volume of the incoming 

air depend on the amount of air being removed. Negative-pressure air intake pipes are used to 

manage the internal climate by controlling the location, speed, and direction of fresh air entry. 

Meanwhile, the exhaust fan regulates the volume of air entering the building. Figure I.11 illustrates 

this system. The exhaust fan(s) in the poultry house create a slight vacuum, allowing air to flow 

into the barn through the designated inlets. 

 

Figure I. 11: Negative-pressure air intake pipes[2]. 

I.7.3.1 Inlet speed : 

The speed of fresh air entering the poultry house is influenced by the pressure difference 

between the interior and exterior environments. This pressure difference is determined by the 

number and size of the air inlets. By controlling this pressure differential, the airflow pattern inside 

the building, as well as the negative-pressure air intake pipes used to regulate the internal climate, 

can also be controlled.  



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I.7.3.2 Inlet area : 

The exhaust fan should generate a static pressure of approximately 12–25 Pa to ensure 

effective control and distribution of air throughout the poultry house. 

I.7.3.3 Air inlet control : 

The design of air inlets should be strategically positioned, as the direction of airflow is 

influenced by external weather conditions, as well as the age and class of the chickens. During the 

colder months, air inlets should direct air toward the ceiling, while in hotter months, the airflow 

should be directed towards the floor. 

 

Figure I. 12: Air inlet control in poultry houses. 

I.7.4 Types of inlet ventilation system : 

I.7.4.1 Cross ventilation : 

The exhaust fans are located on one side of the poultry house, with the air intake pipes 

positioned on the opposite side. This setup is ideal for smaller poultry houses (less than 10 meters) 

as it may create uneven environmental conditions in larger buildings [2]. 

  



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I.7.4.2 Ventilation via the sidewall : 

Exhaust fans are installed on both sides of the building walls, below the air intake pipes. The 

distance between the exhaust fans and the intake pipes should be at least twice the diameter of the 

fan. The exhaust fans draw air through the floor, directing it towards the center. This setup is also 

suitable for houses with a maximum width of 12 meters [2]. 

I.7.4.3 ventilation attic inlet : 

In this ventilation setup, exhaust fans are positioned low on the walls, while air inlets are 

located in the ceiling. This design requires proper ceiling insulation and is particularly effective in 

hot climates. It is a highly recommended ventilation method for raising laying hens [2]. 

 

Figure I. 13: Overhead ventilation in poultry house. 

I.7.5 Air movement inlet ventilated house : 

The exhaust fans are positioned on the lower sides, and the air inlets are located in the ceiling. 

This ventilation system requires proper ceiling insulation and is most effective in hot climates. It 

is a highly recommended method for raising laying hens [2]. 



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Figure I. 14:Air movement inside the poultry house. 

I.7.6 Tunnel ventilation system : 

The tunnel ventilation system is designed to ensure the appropriate air velocity and exchange 

rate. However, the required air speed depends on the specific type of bird being raised. Table 2 

outlines the recommended air velocities for different types of poultry [2]. 

Table I. 3: Air velocity recommendations for tunnel-ventilated dwellings. 

House type Air speed (m/s) 

Broilers 2.5–3 

Pullets 1.75–2.25 

Broiler breeders 2.25–3 

Commercial layer 2.5–3 

I.7.6.1 Tunnel fan capacity and air velocity : 

The capacity of the tunnel fan is calculated using the same method as the inlet ventilation 

system. However, unlike the inlet system which relies on a circulating fan to maintain adequate air 

velocity the required average air velocity inside the tunnel house is determined using the formula 

below [2]. 

Air velocity tunnel fan capacity/ (cross sectional area of the house) ×3600 

Where: 



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 Air velocity (m/s) 

 Tunnel fan capacity (m³/h) 

 Cross-sectional area (m²) 

However, it is important to note that the cross-sectional size of the house negatively affects 

airspeed. Therefore, long and narrow houses with lower ceilings are recommended [2]. 

Consequently, the following equation can be used to determine the required air velocity. 

Tunnel fan capacity =desired air velocity/(cross−sectional area of the house)×3600 

Where: 

 Desired air velocity (m/s) 

 Tunnel fan capacity (m³/h) 

 Cross-sectional area (m²) 

In situations where space is limited, air deflectors with a large cross-sectional area can be 

installed to reduce the effective cross-sectional area inside the poultry house. These deflectors are 

curtain-like structures that extend 2.5–3 meters from the ceiling toward the floor. Research has 

shown that air deflectors can increase air velocity for a range of 1.2 meters upwind and 6–9 meters 

downwind. However, to prevent disruptions in fan performance and air exchange due to increased 

static pressure, deflectors should be installed at a minimum height of 2.5 meters above the ground 

[2]. 

I.7.6.2 Air velocity distribution : 

Air velocity in a tunnel house is generally assumed to be uniform throughout. However, it can 

vary slightly due to factors such as the smoothness of building surfaces, the presence of poultry 

equipment, and other obstacles that deflect airflow. The difference in air velocity between the 

center and the sides of the house can range from 15% to 40% [5]. 

  



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I.7.6.3 Bi-directional tunnel house : 

To achieve maximum air speed in a tunnel house, it is advisable to place the fans at one end 

and the air intake at the opposite end. However, if the poultry house exceeds 180 meters in length 

and the required air velocity in a single direction is more than 3.5 meters per second, a bi-directional 

tunnel ventilation system should be implemented. In this setup, fans are installed on the end walls 

of the building, and the air intake is located in the center. To ensure a consistent temperature 

difference between the intake and the fans, the air velocity in both directions is reduced to half of 

the required velocity, while still maintaining the same air exchange rate [5]. 

I.7.6.4 Tunnel fan placement : 

Fans can be installed either on the end walls or on the side walls near the ends of the building, 

and their performance remains largely unaffected by their placement. However, as the width of the 

poultry house increases, placing fans on the side walls may lead to the formation of dead zones 

with reduced airflow. 

I.7.6.5 Tunnel inlet opening : 

If evaporative cooling pads are not used, it is recommended that the intake area be at least 10% 

larger than the cross-sectional area of the house. For tunnel houses equipped with evaporative 

cooling pads, the intake size depends on the type of pad used. It is also advised to position the 

intake opening on the sidewall as close to the end wall as possible. However, if the house is wider 

than 15 meters, the inlet ports should be installed on the end wall [2]. 

I.7.6.6 Cool weather inlet system for tunnel ventilated houses : 

Using a tunnel ventilation system is recommended during hot weather, as cooler conditions 

tend to decrease the air exchange rate. Therefore, it is suggested that the existing intake system be 

capable of handling at least 60% of the tunnel fan capacity before transitioning to tunnel ventilation. 

This allows for easier switching between systems during cooler weather [2]. 

  



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I.7.7 Poultry exhaust fans : 

I.7.7.1 Types of fans : 

I.7.7.1.1 Exterior and interior shutter fans : 

This is the simplest type of exhaust fan. When not in use, its shutters remain closed. However, 

an external shutter can hinder airflow, as air tends to spin off the blades upon contact. In contrast, 

fans with internal shutters have them positioned on the intake side, which minimizes airflow 

obstruction. These fans also feature larger shutters, allowing for greater air movement. According 

to Daghir [2], this design improves airflow by 5–10% compared to fans with external shutters. 

I.7.7.1.2 Discharge cone fans : 

It improves fan performance by 5–10% by making the transition from drawing 

to fans easier [5]. 

I.7.7.1.3 Belt-drive fans : 

A simple pulley mechanism drives the fan blades. To avoid belt slippage, it may 

be updated with an automated belt tensioner [5]. 

I.7.7.1.4 Direct-drive fans : 

The blades of the fan are directly linked to the motor shaft, avoiding the need 

for a belt. In comparison to belt-driven fans, they are less energy efficient [2]  



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I.8 Conclusions : 

This chapter reviews and synthesizes existing literature on broiler chickens and their housing 

systems, underscoring the pivotal role of environmental design in enhancing bird performance, 

welfare, and overall productivity. The analysis concludes that heat loss in birds occurs through 

convection, radiation, and conduction only when ambient temperatures are below or within their 

thermoneutral zone. In tropical regions, the design of open, well ventilated housing has been 

explored to create optimal environments for broiler production. Research indicates that heat loss in 

birds is amplified with increased air volume and velocity. 

Attention to architectural elements such as building orientation, roof slope, roof overhang, 

landscaping, building height, width, and length is essential for effective housing design. It is 

evident that structures incorporating natural ventilation are critical for achieving successful broiler 

production. Additionally, integrating cooling mechanisms such as fogging systems, sprinklers, and 

circulating fans into naturally ventilated housing systems has been shown to enhance bird 

performance significantly. 

In situations where environmental temperatures are excessively high and unbearable for birds, 

mechanically ventilated open housing systems have been introduced. These systems, particularly 

tunnel and intake ventilation designs, have proven effective in sustaining productive broiler 

farming even under harsh climatic conditions. However, designing an efficient mechanically 

ventilated house requires careful consideration of several factors, including fan capacity, heat 

generated by the birds, inlet sizes, installation levels, positioning of inlet pipes and exhaust fans, 

and the capacity of circulation fans in inlet-ventilated systems. Proper planning and execution of 

these elements are vital to ensuring optimal performance and welfare of broilers in challenging 

environments. 



 

 

Chapter 02 
Methodology 

 



Methodology 

 

30 

 

II.1 Introduction : 

Poultry farming is an energy-intensive industry that requires substantial energy inputs to 

maintain an optimal indoor environment conducive to bird health and high productivity in meat 

and egg production. The need for heating during colder months, cooling and ventilation during hot 

periods, and consistent lighting makes energy demand continuous and critical. In response to rising 

energy costs and environmental concerns, numerous studies and practical applications have 

focused on integrating renewable and sustainable energy technologies into poultry farming. These 

technologies include photovoltaic (PV) systems, solar thermal collectors, hybrid 

photovoltaic/thermal (PV/T) systems, thermal energy storage, ground, air, or water source heat 

pumps, as well as advanced lighting and radiant heating solutions. Compared to conventional 

poultry houses, these modern systems have demonstrated the ability to reduce energy consumption 

by up to 85%, with estimated payback periods ranging from 3 to 8 years. 

Among the most promising developments is the emergence of Hybrid Renewable Energy 

Systems (HRES), which combine multiple energy sources to meet both thermal and electrical 

demands more efficiently. A particularly effective configuration is the integration of solar 

photovoltaic systems with geothermal technologies, such as Earth-Air Heat Exchangers (EAHE). 

This hybrid approach leverages the abundant solar irradiance in regions like Algeria to generate 

electricity during the day, while geothermal systems provide stable, passive heating or cooling by 

utilizing the relatively constant subsurface temperatures. The synergy between these two sources 

creates a resilient, cost-effective energy system that reduces dependence on fossil fuels, enhances 

system reliability, and ensures optimal indoor climate control in poultry houses. 

In this chapter, we will provide a detailed analysis of energy-saving heating, ventilation, and 

air conditioning (HVAC) systems in poultry farming. We will also estimate the energy 

requirements of broiler chickens based on their growth cycle, activity levels, and seasonal breeding 

conditions. Particular focus will be given to the application of these systems within the Algerian 

context, and especially in El Oued Province, where extreme temperature variations and high solar 

potential make the use of solar-geothermal hybrid systems especially advantageous. This review 



Methodology 

 

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aims to identify the most effective strategies for improving energy efficiency, reducing emissions, 

and enhancing sustainability in modern poultry production. 

II.2 Poultry production in Algeria : 

The Algerian poultry industry produces an annual average of 340,000 tons of white meat and 

over 4.8 billion eggs. The sector involves approximately 20,000 farmers and provides employment 

for about 500,000 people. However, it depends heavily on imported inputs, with 80% of its 2.5 

million tons of poultry feed - mainly consisting of corn and soybean meal  as well as three million 

breeder birds, veterinary products, and equipment being sourced internationally. This reliance on 

foreign markets, particularly for corn and soybean meal which constitute more than 75% of poultry 

feed, represents the primary constraint on the industry's development. 

The current organization of Algeria's poultry sector originates from government development 

policies implemented in the 1980s. Today, producers face numerous challenges including supply 

chain issues, rising costs, reduced state involvement, and difficulties in marketing their products. 

These problems have led many experienced farmers to leave the industry, resulting in a significant 

loss of expertise. Simultaneously, the sector is undergoing modernization to meet international 

standards, particularly in preparation for Algeria's expected accession to the World Trade 

Organization (WTO) and its partnership agreement with the European Union. This integration will 

lead to increased competition and requires enhanced cooperation between various stakeholders 

(professional organizations, inter-professional associations) and relevant government agencies 

(industry, agriculture, and trade ministries). Establishing an appropriate institutional framework is 

crucial for developing, implementing, and monitoring policies for the poultry meat and egg 

sectors[66]. 

The global emergence of avian influenza (H5N1 virus) also affected Algeria's poultry 

production, despite no cases being detected in the country. White meat production decreased 

significantly by 15.5% in 2005 compared to 2004[68] (Figure II.1), though it rebounded sharply in 

2006 with a 68% increase to reach 241,166 tons[68]. During the avian flu crisis, approximately 

80% of Algeria's 20,000 poultry producers temporarily ceased operations[67]. 



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Figure II. 1: Evolution of white meat production in the last decade [69]. 

II.3 Geothermal energy  

refers to the heat that comes from deep within the Earth. The term “geothermal” combines two 

Greek words: geo, meaning earth, and therme, meaning heat. Since the Earth's interior continuously 

produces heat, geothermal energy is classified as a renewable resource. This natural heat is utilized 

for various purposes, including residential heating and electricity generation. 

 

Figure II. 2: Geothermal energy. 

Geothermal energy stands out as one of the most energy efficient technologies available today, 

offering the following advantages: 



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 effective for both heating and cooling livestock sheds. 

 near-zero carbon footprint. 

 easily scalable for various applications. 

 has the potential to reduce energy bills by 50% to 70%. 

 delivers consistent base-load power, unaffected by weather conditions like sun or wind. 

Geothermal heating and cooling involves utilizing the constant underground temperature 

found at depths of two to three meters to regulate indoor temperatures [103]. 

 

Figure II. 3: Schematic diagram of the geothermal heat pump (GHP) system for the broiler 

house [103]. 

II.3.1 Working principle of geothermal energy: 

In Algeria, depending on the location, the soil temperature at a depth of two to three meters 

remains relatively constant throughout the year, typically ranging from 22°C to 24°C. Geothermal 

heating and cooling systems use a closed-loop network of underground pipes filled with fluid to 

tap into this thermal energy. The ground loop collects heat from the earth and transfers it to a heat 

pump. This pump amplifies the heat and distributes it throughout the poultry house, while also 



Methodology 

 

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extracting excess warmth from the interior and channeling it back into the ground through the 

same loop system [105]. 

II.3.2 The main components of a geothermal energy system : 

II.3.2.1 The heating and cooling pump : 

A heat pump is an electrically operated system that moves heat from a cooler area (the source) 

and transfers it to a warmer area, such as poultry houses. The same principle is used in cooling 

mode, where the system removes heat from a warmer zone (the ground) and transfers it to a cooler 

space [89]. 

Ground-source heat pumps consist mainly of two essential components: a ground heat 

exchanger and a heat pump unit. Unlike air-source heat pumps, which feature an external heat 

exchanger, ground-source systems incorporate the heat exchanger inside the building [118]. 

II.3.2.2 Ground heat exchanger : 

 Open Loop : 

In an open-loop system, a groundwater bore serves as the primary heat source. Groundwater 

is pumped into the heat pump unit, where heat is extracted before the water is safely discharged in 

an environmentally responsible way. These bores are highly effective sources of thermal energy, 

as groundwater typically maintains a consistent temperature year-round [101]. 

Open systems utilize the thermal energy stored in underground water bodies. Water is drawn 

from a well and directed straight to the heat exchanger, where the heat is extracted. Afterward, the 

water is discharged into a surface water body, as illustrated in Figure II.4 [101]. 



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Figure II. 4: open loop system[101]. 

 Closed Loop : 

A closed-loop system utilizes a continuous circuit of underground polyethylene (poly) piping. 

This pipe network is linked to the indoor heat pump, forming a sealed loop below the surface that 

circulates a mixture of water and environmentally safe antifreeze. Unlike open-loop systems that 

rely on groundwater from a bore, closed-loop systems continuously recirculate their heat-transfer 

fluid within a pressurized, closed-loop environment [80]. 

 

Figure II. 5: spiral closed loop system [80].  



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II.4 VENTILATION PRINCIPLES : 

II.4.1 Economic importance of ventilation : 

Modern broiler chickens have undergone significant genetic improvements to meet market 

demands, resulting in accelerated growth rates and enhanced carcass yields. However, these 

advancements particularly the increased breast muscle development have also made the birds more 

vulnerable to environmental stressors such as heat, ammonia, and airborne particulates. 

Current research indicates that a substantial portion of performance variation among broiler 

flocks can be directly linked to the effectiveness of environmental management systems. Precise 

regulation of two key factors proves critical: 

1. Temperature control 

2. Air quality maintenance 

These findings underscore the heightened importance of optimized housing conditions in 

contemporary poultry production systems. 

 

Figure II. 6: Ventilation in poultry houses. 

The broiler industry's primary goal is efficient production of market-ready chicken meat. 

Achieving this requires meticulous maintenance of optimal housing conditions, as environmental 

factors directly impact: 

- Flock health status 

- Target live weights 

- Feed conversion efficiency 



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- Carcass quality and yield 

Suboptimal temperature and air quality control negatively affect all these parameters, 

ultimately reducing profitability. The difference between mediocre and exceptional flock 

performance often lies in environmental management. 

Modern broiler genetics have been developed for rapid growth, but this potential can only be 

realized through consistent feed intake. Elevated temperatures suppress appetite, limiting 

consumption and growth. Therefore, maximizing genetic potential fundamentally depends on 

advanced ventilation systems that maintain ideal in-house conditions. 

II.4.2 Air quality : 

Air consists primarily of nitrogen, oxygen, and carbon dioxide, with water vapor constituting 

less than 1% of its composition. Despite its minimal proportion, water vapor plays a critical role in 

determining air properties due to its biological importance and exceptionally high latent heat 

capacity - the substantial energy required to transform water from liquid to vapor state. This 

characteristic means the small amount of water vapor present often contains most of the air 

mixture's total heat energy. In poultry housing environments, air quality deteriorates when 

contaminants exceed acceptable thresholds. These pollutants include solid particulates, 

microorganisms (bacteria, fungi, and viruses), and harmful gases like ammonia, hydrogen sulfide, 

and carbon dioxide. While these contaminants are naturally present to some degree, their 

concentrations can be effectively managed through proper environmental control systems to 

maintain optimal poultry house conditions. 

II.4.3 Natural ventilation : 

Natural ventilation, as the term suggests, is a technology that utilizes natural forces to supply 

fresh air to poultry facilities. Air is exchanged through the structure's inlets and outlets. It is 

essential to understand the distinctions between natural and mechanical ventilation systems. In 

mechanical ventilation systems, air exchange fans can be adjusted to achieve the desired rate of air 

exchange. Both thermal buoyancy and wind are influenced by unpredictable weather changes, 

which differentiates natural ventilation control [74].  

This system operates in "single-sided open," "curtain-sided," or "natural" buildings. Fans may 

also be used inside the structure to circulate air. Figure II.7   



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Figure II. 7: Ventilation Natural. 

II.4.4 Electric ventilation : 

Enclosed or climate-controlled buildings typically feature solid side walls or curtains that 

remain closed during operation. As a result, electric ventilation systems and fans are employed to 

circulate air within the building. Figure II. 8 

 

Figure II. 8: Electric ventilation. 

II.5 The main factors and ingredients in raising chickens : 

II.5.1 temperature : 

Chicks require warmth, but this need decreases gradually as they grow. Table 2 shows the 

ideal nursery temperature based on the age of the chicks. The actual temperature should not differ 

from the ideal temperature by more than 2°C.   



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Table II. 1: represents the optimum temperature for broiler chickens. 

Chickage (number of days) Temperature under the 

heater 

Temperature in the poultry 

house 

1 35 C ° 27C ° 

2→10 32 C ° 26C ° 

11→14 30 C ° 25 C ° 

15→ 17 29 C ° 24 C ° 

18→20 27C° 23C ° 

21→24 26 C ° 22 C ° 

25→27 25 C ° 22 C ° 

28→31 23 C ° 21 C ° 

34→37 21 C ° 20 C ° 

38→40 20 C ° 19 C ° 

41→45 18 C ° 18 C ° 

 

II.6.2 Humidity and litter : 

The litter should always be kept clean and dry, as wet litter poses a significant risk to bird 

health. Characteristics of good litter include:   

- Made of sawdust (mature) or rice husk;   

- Clean, dry, and slightly elastic, not sticking excessively to hands or shoes;   

- A thickness of 8 cm during the first week of a bird’s life, reducing to about 6 cm thereafter;   

- Warm to the touch by the time birds reach 11 days old, as the litter generates heat from 

decomposition;   

- Maintained clean and dry, especially when considering a density of 10 birds/m²;   

- If the litter becomes wet or sticky in the entire house or in certain areas, it indicates a problem 

that needs addressing;   

- Litter near feeders should be removed if mixed feed is present in it. Otherwise, chickens may 

consume grain scattered outside the feeder along with the litter, leading to digestive issues and 

diarrhea.   



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Figure II. 9: Wood carpentry in the poultry house. 

The capacity of air to hold varying amounts of water vapor, expressed as relative humidity, is 

another critical factor that significantly impacts pathogen growth and litter conditions. While 

humidity does not directly affect chicken behavior, it can lead to indirect issues. For instance, 

during dry weather, low humidity causes dust accumulation, which irritates the respiratory system 

and facilitates the spread of bacterial infections. Conversely, a damp environment makes chickens 

more susceptible to cold stress, especially at lower temperatures, and promotes the formation of 

crusts on the ground, increasing the risk of germs and parasites. The ideal relative humidity for 

raising chickens ranges between 40% and 75%; however, deviations from this range may lead to 

health problems, such as respiratory diseases [75].   

Table II. 2: represents the optimum humidity for broiler chickens. 

Chickage (number of days) Humidity in the poultry house 

1 62%-60% 

7 60%-50% 

14 50%-46% 

21 46%-40% 

28-45 40% 



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II.5.3 Lighting : 

Light is a crucial factor that supports animal growth, as it enables continuous feeding. Proper 

lighting management in poultry houses is essential for optimal performance.   

- From 1 to 15 days: 3–5 W/m² for 24 hours.   

- 3–4 weeks: 1–2 W/m² for 10–14 hours per day [76].   

During the first two days, maximum lighting (23–24 hours) with an intensity of approximately 

5 W/m² is critical to encourage water and feed intake. The purpose of this lighting is to help chicks 

locate feeders and drinkers. However, excessively bright lighting in hot areas should be avoided to 

reduce stress. Nighttime lighting during cooler periods is necessary to maintain proper 

consumption levels. To minimize activity and promote growth, broilers should be kept in semi-

darkness.   

Various light sources can be used for broilers (Fig II.9). The most common types include 

incandescent, fluorescent, and LED lighting:   

- Incandescent lamps provide a good spectral range but are not energy-efficient [77].   

- Fluorescent lamps  are more efficient than incandescent lamps but lose intensity over time 

and must be replaced before complete failure.   

- LED lights (Light Emitting Diodes) are highly efficient, offer customizable color options, 

and have a longer lifespan, though their initial cost is higher [78].   

 

Lamp Halogen 45w            lamp fluorescent 16w             lamp LED 6w 

Figure II. 10: Types of light sources that can be used for broilers. 

Low light intensity during the day (overly dim lighting) can negatively impact mortality rates, 

growth, and overall broiler welfare. Insufficient lighting may also result in:   



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- Impaired eye development.   

- Increased risk of foot injuries.   

- Reduced activity levels and altered resting behaviors, such as decreased dust bathing and 

scratching.   

- Disruption of physiological rhythms, as birds may struggle to distinguish between night and 

day [79].   

Table II. 3: Lighting Program Recommendations. 

Chicken age (in days) Duration of the light period 

1 to 4 24 hour 

5 to10 22 hour 

10 to the end. 24 hour 

II.5.4 Heating equipment: 

 Electric brooder : 

It consumes less fuel, offers a wide range of applications, and is easy to adjust and maintain.   

 

Figure II. 11 : Electric chicken heater. 

II.6 The identification of traditional and modern poultry farmers : 

It is widely recognized that poultry farming in Algeria has gained significant attention across 

all regions of the country. The practices in poultry farming range from traditional to modern 

methods, and this is where the key distinction lies. Traditional methods lack even the most basic 



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modern and advanced tools used in poultry houses, such as heating, ventilation, air conditioning, 

and lighting. On the other hand, modern methods are defined by the use of advanced technology in 

chicken rearing, enabling farmers to achieve higher productivity and superior quality compared to 

traditional practices. 

 

Figure II. 12: traditional and modern poultry farmers. 

II.6.1 The location of the poultry house where the study was carried out : 

The study area is situated in the southeastern part of the country, approximately 670 kilometers 

away from the capital, Algiers. It is geographically located between latitudes 33° and 34° north and 

longitudes 6° and 8° east, within the northern desert region of the eastern race. The study focuses 

on the municipality of Oued El-Alanda. 



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Figure II. 13: Location of El-Oued Province in Algeria. 

II.6.2 Breeders ages in Oued Souf : 

It has been observed that 2% of traditional poultry farmers are 55 years old, while 13% 

represent other age groups. On the other hand, the data indicates that most poultry farmers fall 

within the ages of 28, 35, 44, 53, 65, and 70 years. Notably, 33% of breeders are over 45 years old 

[23].   

II.6.2.1 level of poultry farmers : 

 

 (A)  (B) 

Figure II. 14 : (A) Traditional poultry farmers. - (B) Modern poultry farmers. 

The figure above illustrates that 27% to 33% of poultry farmers possess a terminal or 

university-level education. Conversely, there is a percentage range of 14% to 13% of poultry 

farmers who are illiterate or have only primary or secondary education, respectively. Figure II.14 



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further highlights that 80% of poultry farmers have attained a university-level education, while 7% 

have a terminal-level education.   

II.6.2.2 Poultry farmer's adjectival : 

 

 (A)  (B) 

Figure II. 15 : (A) Traditional poultry farmers - (B) modern poultry farmers. 

The data shows that 60% of poultry farmers own traditional poultry houses, while 40% are 

tenants. In contrast, for modern poultry houses, 80% of poultry farmers are owners, and 20% are 

tenants.   

II.7 Poultry building characteristics  

 (A)  (B) 

Figure II. 16 : (A) Type of traditional building - (B) Type of modern building. 

(A) shows that (60%) type of traditional buildings are dark than (40%) are light. 

The graph in (B)  shows that 93% of typical modern buildings are dark.  



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II.7.1 Capacity of buildings: 

 

Figure II. 17: Capacity of buildings (traditional, modern). 

It is observed that more than 26% of traditional poultry buildings have a capacity of 6,000 

birds, while over 6% have a capacity of 2,000 birds. A majority of 13% fall within the range of 

1,500 to 5,000 birds. In contrast, 33.3% of modern poultry buildings have capacities ranging from 

8,000 to 50,000 birds, while more than 6.7% accommodate 5,500 birds, and others house 5,000 

birds (26%). Figure II.17. 

II.7.2 Chick density per  : 

The graph in Figure II.18 shows that the highest density recorded is more than 40 chicks/m², 

accounting for 60% of the observations. The second-highest density is 40 chicks/m², while the 

lowest density is associated with a timeframe of 40 months, with percentages of 27% and 13%, 

respectively.   

 

 (A)  (B) 

Figure II. 18 : (A): Chick density / 𝑚2 traditional – (B): Chick density /𝑚2 modern. 



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II.7.3 Area of buildings :  

 

Figure II. 19 : Surface area of traditional and modern buildings. 

This graph indicates that the majority of traditional buildings have surface areas ranging 

between 180 m² and 750 m², while more than 6% of them measure exactly 200 m². On the other 

hand, it is shown that 33.3% of modern buildings have a surface area of 4,500 m², while 6% of the 

buildings measure 556 m². Additionally, 13% to 20% of modern buildings have surface areas 

ranging between 500 m² and 798 m². 

II.7.4 The number of chicks in buildings : 

 

Figure II. 20: Number of chicks in buildings (traditional and modern). 

The data reveals that the majority of traditional poultry houses, representing 13.3%, have a 

chick population ranging between 1,500 and 6,000 birds, while 6.7% of these houses house exactly 

2,000 chicks. Conversely, in modern buildings, 33.3% of the structures accommodate chick 

populations ranging between 5,000 and 50,000 birds. (Figure II.20).  



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II.8 Building equipment and materials : 

II.8.1 Type of drinkers :  

 

 (A)  (B) 

Figure II. 21: (A) Type traditional drinkers.- (B) Type modern drinkers. 

The data indicates that 87% of traditional buildings use siphoid drinkers, while 13% utilize 

linear nipple drinkers. (A). In contrast, 67% of modern buildings are equipped with linear nipple 

drinkers, and 33% use siphoid (round) drinkers. (B). 

II.8.2 Type of feeders : 

 
 (A)  (B) 

Figure II. 22 : (A) Traditional feeder type. - (B) Modern feeder type. 

This graph shows that (87%) in traditional buildings used linear feeders and 

13% they used automatic plate feeders. (A), on the other hand that 93% of modern 

buildings use automatic plate feeders. (B).  



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II.8.3 Type of heating : 

 

 (A)  (B) 

Figure II. 23 : (A) Type of traditional heating - (B) :Type of modern heating. 

The data indicates that over 80% of traditional buildings employ radiant heating, while only 

13% use forced air systems. In contrast, (A) shows that 80% of modern buildings rely on forced air 

heating, with the remaining 20% utilizing radiant heating (B). 

II.8.4 Starting temperature : 

 

Figure II. 24 : Starting temperature of traditional and modern buildings. 

The graph illustrates that 53% of traditional buildings operate at a temperature (T°) of 33°C, 

while more than 6% operate at T° = 31°C. Additionally, 13% of these buildings function within a 

temperature range of 30°C to 35°C. In contrast, the data shows that 80% of modern buildings use 

T° = 33°C, with a smaller proportion between 7% and 13% operating at T° = 31°C and T° = 32°C.    



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II.8.5 Warm-up time : 

 

 (A)  (B) 

Figure II. 25 : (A) Traditional heating time. - (B) Modern heating time. 

The heating time (preheating) achieved is 36 to 48 hours for 47% of the cases, whereas in 

traditional buildings, the preheating time is 24 hours for 53% of the cases. (A) highlights this 

contrast. On the other hand, (B) shows that 100% of modern buildings complete their preheating 

within 24 hours. 

II.8.6 The period of light : 

It has been observed that 100% of buildings (traditional and modern) use the 

light period (23h-24h). 

II.8.7 Type of ventilation : 

 

 (A)  (B) 

Figure II. 26 : (A) Type of traditional ventilation - (B) Type of modern ventilation 

We observe that 47% of cases achieve a heating time (preheating) of 36 to 48 hours, while in 

traditional buildings, 53% achieve a preheating time of 24 hours. (A) illustrates this difference. On 

the other hand, (B) shows that 100% of modern buildings complete their preheating within 24 

hours.  



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II.8.8 Number of mortalities in batch : 

 

Figure II. 27: Number of deaths in batch arrivals (traditional, modern). 

In this graph, it is shown that in traditional buildings, 47% experience no mortality, while 

between 13% and 27% have mortalities ranging from 10 to 20 subjects. However, in modern 

buildings, 67% show no mortality, and between 7% and 13%, there are mortalities involving 6 to 

10 subjects. Figure II.27 

II.8.9 Weight of each day 1 chick : 

This graph indicates that in traditional breeding, 47% of the chicks on the 1st day weigh 40g, 

and between 13% and 25%, the weights range from 35g to 62g, respectively. However, in modern 

breeding, it is recorded that 33% of the chicks weigh 40g, while between 13% and 17%, the weights 

range from 45g to 50g. (Figure II.28) 

 

Figure II. 28: Weight of each day 1 chick (traditional, modern).  



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II.8.10 First week chick weight : 

 

Figure II. 29: Weight of each chick in the 1st week (traditional, modern). 

In traditional breeding, it is observed that the weight of the chicks during the 1st week varies 

from 50g to 180g. However, in modern breeding, the weights are higher, ranging from 170g to 

280g. Figure II.30 

 

Figure II. 30 : Measuring chick weight 1st week. 

II.8.11 Weight of each chick of the 2nd week : 

 

Figure II. 31 : Weight of each chick of the 2nd week (traditional, modern). 



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In this graph, it is shown that in traditional breeding, 40% of the chicks weigh 250g, and the 

same percentage of 13% of the remaining chicks have the following weights: 150g, 300g, 360g, 

and 370g. Additionally, 6% of the chicks weigh 254g. In modern breeding, however, 20% of the 

chicks weigh 370g, and the same percentage of 13% of the remaining chicks have weights ranging 

from 300g to 570g, while 6% of the chicks weigh between 420g and 500g. Figure II.32 

 

Figure II. 32 : Measuring chick weight 2nd week. 

II.8.12 Weight of each chick in the 3rd week : 

In traditional buildings, it is recorded that only 40% of the chicks weigh 700g, and for the rest, 

the same percentage of 13% have weights ranging from 450g to 720g. With a low percentage, some 

chicks weigh 723g. However, in modern buildings, 20% of the chicks weigh 880g, while an equal 

percentage of 13% for the rest have weights between 800g and 945g, and 6% of the chicks weigh 

between 838g and 950g. Figure II.33 

 

Figure II. 33 : Weight of each chick of the 2nd week (traditional, modern).  



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