Ammonia, dust, and pathogens in intensive broiler sheds cause chronic respiratory disease and eye damage affecting billions of birds annually.
Poor air quality in broiler houses is a pervasive welfare problem largely invisible to consumers. Chronic ammonia exposure causes persistent eye irritation and corneal damage — birds squint, avoid light, and show reduced activity. Respiratory disease causes labored breathing, reduced feed and water intake, and fatigue. Because broilers are slaughtered at 35–47 days, even brief periods of respiratory disease represent a significant proportion of their lives. Ventilation improvements reduce disease burden dramatically but require capital investment and energy costs that producers often resist. The systemic nature of the problem — affecting most conventionally reared birds globally — means the welfare impact is enormous in aggregate.