How Ammonia Levels Impact Broiler Growth and Health
A strong ammonia smell inside a poultry house is often a warning sign that concentrations have already reached unsafe levels for birds. People typically do not notice ammonia until it reaches about 20 to 30 parts per million (ppm), yet poultry welfare guidelines recommend maintaining levels below 25 ppm to protect bird health and meet certification requirements.
Repeated exposure can dull a person’s sense of smell, meaning farm workers may underestimate ammonia levels over time. Even visitors can become accustomed to the odor within minutes. For poultry, however, elevated ammonia poses serious risks.
High concentrations can damage the respiratory system, weaken immune defenses, and lower overall performance. Studies have shown that broilers exposed to ammonia levels between 25 and 50 ppm can weigh up to half a pound less at seven weeks of age compared to birds raised in low-ammonia conditions.
Ammonia is produced as manure breaks down in litter, forming ammonia gas (NH₃) and ammonium (NH₄⁺). The amount released into the air depends largely on litter pH and moisture.
Keeping litter drier and slightly more acidic can significantly reduce ammonia emissions, while house temperature is generally managed based on bird comfort rather than ammonia control. Even small increases in litter moisture can sharply increase ammonia release.
Measuring ammonia levels is relatively simple using colorimetric tubes that change color when exposed to the gas. Pump-style tubes provide quick spot readings, while diffusion tubes offer average measurements over several hours without the need for a pump.
For the most accurate results, measurements should be taken near bird height, where ammonia concentrations are highest. Consistent monitoring, along with proper litter and ventilation management, helps maintain bird health, productivity, and air quality.
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