Air quality inside poultry sheds — particularly ammonia levels from litter and carbon dioxide from bird respiration — directly affects the health and welfare of housed birds. Ammonia causes respiratory damage and eye problems.
Poultry air quality welfare is measurable and manageable but frequently inadequate in practice. Ammonia levels above 10 ppm cause measurable respiratory irritation, conjunctivitis and reduced activity in both broilers and laying hens. Foot pad dermatitis — swollen, ulcerated foot pads from wet, ammonia-rich litter — is both painful and a sentinel welfare indicator: farms with high foot pad dermatitis scores have consistently poorer air quality. Ventilation design, litter moisture management, stocking density and feed management all affect ammonia production. AHDB guidance provides practical interventions to maintain air quality. Welfare farm assurance audits that include air quality measurement — rather than just visual assessment — produce better outcomes.