Respiratory disease is a major welfare concern in broiler chickens. High stocking densities, poor air quality, and genetic selection all contribute to the problem.
Broiler respiratory welfare is inseparable from genetic and environmental management. Breeds selected for maximum growth rate have proportionally smaller hearts and lungs relative to body mass, creating systemic physiological stress. When combined with high stocking densities that raise ammonia and dust levels, respiratory compromise becomes chronic and widespread. Welfare-positive broiler production uses slower-growing breeds with better physiological capacity, lower stocking densities, and active ventilation management. The Better Chicken Commitment and equivalent European frameworks specifically require use of slower-growing breeds, which significantly reduces respiratory welfare problems alongside other benefits.