Air quality in poultry housing significantly affects respiratory health and welfare, with ammonia, dust, and carbon dioxide causing chronic and acute harm at concentrations common in commercial settings.
Air quality is a welfare determinant that affects every bird in a flock simultaneously and persistently. Ammonia generated from litter breaks down continuously irritates eyes and respiratory mucosa, causing keratoconjunctivitis, tracheitis, and secondary bacterial pneumonia. Birds in high-ammonia environments show behavioral signs of discomfort including reduced activity and feed intake. Carbon dioxide accumulation in poorly ventilated houses causes hypoxia affecting bird health and performance. The welfare harm from poor air quality compounds with other housing welfare issues: birds already experiencing leg disorders or other health problems are more vulnerable to respiratory compromise. Adequate ventilation that maintains ammonia below 20 ppm and provides fresh air exchange is achievable in modern housing systems and represents a basic welfare requirement.