Farmed Broiler Chicken Heat Stress Welfare

Heat stress in broiler chicken farming causes acute suffering, high mortality, and significant economic losses. As climate change worsens, managing heat stress is an increasingly critical welfare challenge.

Key Facts

Broiler chickens are particularly vulnerable to heat stress due to selective breeding for large muscle mass with limited heat dissipation capacity
Broilers have no sweat glands and rely on panting and wing-spreading to regulate body temperature
Heat stress begins at approximately 27°C — at temperatures above 38°C, mortality increases rapidly
Heat stress events during UK and European heatwaves have caused mass mortality events killing millions of birds
Stocking density directly affects heat stress risk — higher densities raise litter temperature and reduce airflow per bird
Climate projections indicate increasing frequency of extreme heat events in major broiler-producing regions globally

Welfare Considerations

Broiler heat stress is a welfare emergency that is becoming more frequent and severe with climate change. During heat waves, broilers — bred for rapid growth at the expense of thermoregulatory capacity — can experience acute distress, respiratory failure, and mass death in poorly ventilated sheds. The suffering involved in heat-related death is severe: birds show extreme panting, prostration, loss of coordination, and convulsions before death. Climate-adaptive housing design — tunnel ventilation, evaporative cooling, insulated roofing, and reduced stocking densities — significantly reduces heat stress risk but requires capital investment that many producers delay or avoid. Reducing stocking densities is one of the most effective heat stress management tools as it reduces heat load per bird, but it reduces throughput and profitability. Emergency protocols for heat events including lighting adjustments, water supplementation, and early morning ventilation provide some mitigation. The trend toward faster-growing broiler breeds that are even more heat-sensitive warrants reversal in favor of breeds with better thermoregulatory capacity.

What You Can Do

Support the Better Chicken Commitment, which advocates for slower-growing breeds with better heat tolerance
Advocate for mandatory climate-adaptive housing requirements in broiler farm planning regulations
Choose chicken from certified higher-welfare farms with documented environmental control standards
Support legislation requiring maximum stocking densities that incorporate climate-risk considerations
Raise awareness about how climate change is directly worsening animal welfare outcomes in broiler farming