Heat Stress in Broiler Chickens: Impacts and Mitigation

Broiler chickens are highly susceptible to heat stress due to their rapid growth rate, high metabolic output, and limited ability to dissipate heat, making temperature management critical to welfare and survival.

Key Facts

Broilers begin showing signs of heat stress above 25-28 degrees Celsius; mortality increases sharply above 35 degrees
Modern fast-growing broiler breeds generate significantly more metabolic heat than slower-growing alternatives
Panting is the primary thermoregulation mechanism in chickens; sustained panting causes respiratory alkalosis and electrolyte imbalance
Heat stress increases mortality, reduces feed intake, impairs immune function, and causes welfare suffering
Tunnel ventilation systems move high volumes of air through the house, creating an evaporative cooling effect
Evaporative cooling pads and misting systems can reduce house temperatures by 5-10 degrees Celsius
Electrolyte supplementation in drinking water during heat events helps maintain acid-base balance
Climate change is increasing the frequency and severity of heat events affecting poultry production globally

Welfare Considerations

Heat stress in broilers is a significant welfare concern that causes acute suffering — birds hold their wings away from their body, pant rapidly, show reduced activity, and in severe cases die from hyperthermia. The combination of fast growth rates (which increase metabolic heat production) and confinement in large flocks makes broilers particularly vulnerable. Welfare impacts of heat stress extend beyond mortality: survivors may experience prolonged periods of discomfort, reduced activity, and impaired immunity making them vulnerable to disease. Switching to slower-growing breeds reduces metabolic heat production, improving heat tolerance alongside other welfare benefits. Ventilation system design, backup power for fans, and emergency protocols for power failures are essential welfare infrastructure.

What You Can Do

Support policies and certification schemes that require adequate ventilation and backup power systems in poultry housing
Choose chicken products from slower-growing breeds that are more heat-tolerant and have better overall welfare outcomes
Engage with campaigns addressing the welfare impacts of fast-growing broiler genetics
Advocate for emergency poultry welfare protocols during extreme heat events
Support research into climate-adapted poultry housing design that maintains welfare under increasing temperatures