Farmed Broiler Heat Stress: A Growing Welfare and Production Challenge

Broiler chickens are highly susceptible to heat stress due to their rapid growth rates and dense feathering. Climate change is intensifying heat stress events in poultry production globally.

Key Facts

Broilers cannot sweat and regulate body temperature through panting, which is metabolically costly
Heat stress above 28 degrees Celsius causes measurable reductions in feed intake, growth, and immune function
Severe heat stress causes mortality events in broiler flocks, with losses of thousands of birds in single events
Fast-growing broiler breeds are more susceptible to heat stress than slower-growing varieties
Evaporative cooling systems and tunnel ventilation reduce heat stress mortality but require energy investment
Climate projections indicate heat stress events will increase in frequency and severity across major broiler-producing regions

Welfare Considerations

Heat stress is both a major welfare problem and a significant production loss for broiler producers, creating aligned incentives for improvement. Birds experiencing heat stress pant continuously, reduce activity, and crowd near water sources. Severe heat stress causes cardiovascular failure in birds already metabolically stressed by rapid growth. Slower-growing breeds are substantially more heat-tolerant and show lower basal stress indicators — a welfare benefit beyond heat stress reduction. Transition to slower-growing breeds combined with improved housing ventilation offers durable welfare improvement as temperatures rise.

What You Can Do

Support broiler welfare certification schemes that require minimum ventilation standards and temperature monitoring
Choose chicken from slower-growing breed programs such as RSPCA Assured or Better Chicken Commitment certified producers
Advocate for building codes that require adequate ventilation in new poultry housing construction
Support poultry industry research into heat-tolerant breeds that maintain good welfare in warming climates