Environmental Challenges in Poultry Farming The Impact of Ammonia and Humidity
Prof. (Dr.) P.K. Shukla and Dr. Amitav Bhattacharyya

Department of Poultry Science,

College of Veterinary Science and Animal Husbandry, Mathura- 281001 (U.P.)

Introduction

Environmental conditions play a crucial role in poultry farming, directly influencing the health, welfare, and productivity of birds. Among various environmental stressors, ammonia levels and humidity are critical factors that must be effectively managed to ensure optimal poultry performance. Both ammonia and humidity are closely linked to litter conditions, ventilation practices, and overall farm management. High concentrations of ammonia and improper humidity levels can lead to serious health issues, decreased feed conversion efficiency, reduced growth, increased mortality, and economic losses.

This article explores the sources, effects, and management strategies related to ammonia and humidity in poultry environments, highlighting their profound impact on commercial poultry operations.

 Ammonia in Poultry Houses

1. Ammonia is a colourless gas with a sharp, irritating Odor that is commonly found in poultry houses. It forms primarily due to the microbial breakdown of uric acid and proteins present in poultry manure. Poor litter management—particularly when litter moisture exceeds 25–30%—combined with high temperatures and insufficient ventilation, accelerates ammonia production. The major sources include poultry litter composed of feces, feathers, bedding, and spilled feed, all of which provide the organic material necessary for microbial activity to generate ammonia.
2. Exposure to ammonia, even at relatively low levels, poses significant health risks to poultry. Ammonia concentrations above 25 ppm can cause damage to the respiratory system, including tracheal and nasal irritation and destruction of cilia, which are essential for clearing mucus and pathogens. This damage makes birds more prone to respiratory infections such as infectious bronchitis, colibacillosis, and Newcastle disease. At higher concentrations (50–100 ppm), ammonia can also lead to eye problems like conjunctivitis and corneal ulcers, as well as skin lesions that compromise animal welfare.
3. Ammonia exposure also affects the overall performance and productivity of poultry. Birds under stress from ammonia tend to reduce their feed intake, resulting in poor feed conversion ratios and stunted growth—particularly evident in broilers. Additionally, chronic exposure suppresses the immune system, reducing birds’ resistance to infections and diminishing their response to vaccinations. This compromised immunity further lowers production efficiency and increases the need for medical intervention, raising production costs.
4. In laying birds and breeders, ammonia has a direct negative effect on egg production. Elevated ammonia levels reduce laying rates and lead to poor eggshell quality. Birds experiencing discomfort may also lay more eggs on the floor rather than in nesting areas, which increases the likelihood of contamination and egg loss. These impacts cumulatively reduce the profitability and efficiency of layer operations.
5. Humidity is another critical environmental factor that influences ammonia production and bird health. In poultry housing, relative humidity (RH) ideally ranges between 50% and 70%, depending on bird age and climatic conditions. Sources of humidity include bird respiration, evaporation from drinkers, wet litter and manure, and external weather conditions. When ventilation is inadequate, moisture accumulates inside the poultry house, raising humidity levels, worsening litter conditions, and promoting ammonia release. Managing both humidity and ammonia is essential for maintaining optimal bird health and ensuring productive, sustainable poultry operations.

Humidity in Poultry Houses

1. Humidity is a crucial environmental factor in poultry housing that directly affects bird health and litter conditions. It refers to the amount of water vapor present in the air, with relative humidity (RH) being the standard parameter used for monitoring. Ideally, RH in poultry houses should be maintained between 50% and 70%, depending on the age of the birds and external weather conditions. Humidity originates from multiple sources, including bird respiration, evaporation from waterers, wet litter and manure, and environmental moisture. Inadequate ventilation often traps this moisture inside the poultry house, leading to increased humidity levels.
2. High humidity can severely impact litter quality, air quality, and bird comfort. Excess moisture results in wet, sticky litter that tends to compact into cakes, creating a breeding ground for bacteria and fungi. This deteriorating litter quality also accelerates ammonia production, compounding respiratory stress for the birds. Elevated humidity reduces oxygen availability in the air and increases concentrations of harmful gases like carbon dioxide and ammonia, exacerbating respiratory diseases and compromising flock health.
3. Thermal stress is another serious concern associated with high humidity. Poultry birds rely on panting for evaporative cooling, especially in warm climates. However, excessive humidity hampers this natural cooling mechanism, significantly raising the risk of heat stress. When temperatures exceed 30°C, the combination of heat and humidity can be lethal, particularly for broilers and heavy breeders, sometimes resulting in sudden death due to acute stress and suffocation.
4. Low humidity, though less frequently encountered, also presents challenges. RH below 40% leads to dry, dusty environments that irritate the birds’ respiratory systems. Dust particles can carry pathogens and increase susceptibility to infections. Furthermore, low humidity causes increased water loss from birds, potentially leading to dehydration. In hatcheries, inadequate humidity can impair embryonic development and reduce hatchability rates, making careful humidity control essential throughout all production stages.
5. Ammonia and humidity are closely interlinked and often act synergistically to worsen environmental conditions. High humidity promotes wet litter, which in turn accelerates ammonia release from manure. Ammonia, combined with high humidity, causes greater damage to the respiratory system than either factor alone. Together, they can increase mortality, reduce productivity, and result in higher condemnation rates at slaughter. Effective monitoring tools—such as colorimetric tubes, electronic ammonia meters, digital hygrometers, and climate control systems—are vital for early detection and management of these hazards in modern poultry operations.

Conclusion

Maintaining optimal environmental conditions in poultry houses is essential for ensuring bird health, welfare, and productivity. Two of the most critical and interrelated environmental factors—ammonia and humidity—have significant impacts on respiratory health, immune response, growth performance, litter quality, and overall profitability in poultry farming.

Ammonia, a harmful gas produced from decomposing poultry manure, becomes a silent but potent threat when not controlled. Even low levels can impair the respiratory tract, suppress immunity, and reduce feed efficiency, while higher concentrations can cause eye damage, skin lesions, and elevated mortality. Similarly, improper humidity—whether too high or too low—can lead to wet litter, increased ammonia emissions, thermal stress, dust buildup, and even poor hatchability in breeding operations.

The interaction between ammonia and humidity creates a vicious cycle: high humidity fosters wet litter, which accelerates ammonia release, further degrading air quality and stressing birds. This combination is particularly dangerous, leading to compounded health issues, lower productivity, and greater economic losses.

Effective management hinges on proactive monitoring and control measures. This includes adequate ventilation, dry and well-managed litter, appropriate stocking density, efficient water systems, and use of ammonia binders or absorbents. Regular use of monitoring tools such as electronic meters and digital hygrometers enables timely interventions.

In conclusion, controlling ammonia and humidity is not just a best practice—it is a fundamental requirement for sustainable and profitable poultry production. As the poultry industry grows increasingly competitive and welfare-focused, adopting comprehensive environmental management strategies is key to achieving long-term success.