Heat stress kills millions of poultry annually and causes significant welfare harm before death. Cooling systems, housing design, and breed selection reduce thermal welfare impacts.
Heat stress in poultry causes acute welfare harm through thermal discomfort, physiological strain, and in extreme cases death from hyperthermia. The welfare timeline of a heat stress event — hours of increasing distress, panting, and physiological deterioration before death — represents significant suffering that is largely preventable through appropriate housing design and cooling systems. Fast-growing broiler breeds with high metabolic rates face compounded vulnerability from their own heat generation alongside environmental heat. Climate change is increasing the frequency of extreme heat events, making heat stress management an increasingly urgent welfare issue for the global poultry industry. Breed selection toward slower-growing birds with lower metabolic rates represents a long-term dual solution that simultaneously addresses both lameness welfare and heat stress vulnerability.