Poor air quality in intensive pig housing causes chronic respiratory disease, eye irritation, and systemic health problems that represent a significant and preventable welfare burden.
Air quality in intensive pig buildings is a chronic, cumulative welfare problem that operates below the threshold of dramatic visible suffering but causes progressive respiratory and systemic harm affecting every animal in the building continuously. Ammonia-damaged respiratory tracts are more susceptible to secondary infection; ammonia-irritated eyes cause chronic discomfort; particulate inhalation causes lung pathology that affects health and productivity. The welfare case for improving ventilation and slurry management is reinforced by the productivity case — healthier respiratory systems mean better growth rates and lower disease costs. Regulatory monitoring of air quality is inadequate in most jurisdictions; welfare-positive producers invest in air quality management as a preventive welfare measure rather than waiting for visible disease.