Heat stress in poultry

Identifying behavioral signs is key to managing heat stress in poultry

Every year, high summer temperatures have important effects on poultry health and welfare. Heat stress occurs when poultry cannot adapt to high environmental temperatures and need to expend energy to maintain their body temperature within the ideal range.

Heat stress can be a problem for any poultry and can affect birds at any age. In addition, heat stress can affect birds in any environment, including indoor or outdoor production systems, backyard environments, at county and state fairs, and during transportation.

The ideal temperature range for most poultry lies between 15 and 24°C (60 and 75°F). The ideal temperature depends on amount of feather cover, age and body weight of the bird.

Costs and consequences of heat stress

Heat stress costs the US poultry industry millions of dollars every year. The consequences of heat stress can be severe, leading to death in extreme cases.

For meat birds, heat stress can reduce meat quality and for egg laying birds, heat stress can result in a drop in egg production and reduced egg quality, including thin egg shells.

High environmental temperatures, combined with high levels of humidity, can be even more problematic.

Recognizing when poultry are at risk of heat stress and identifying heat stress are important in protecting bird health and welfare.

Effects of heat stress on poultry

Heat stressed birds:

Do not grow/develop as well
Are not as efficient at using feed
Are less effective at fighting disease
May pose risks to food safety

Behavioral signs of heat stress

Unlike mammals, poultry lack sweat glands, and behavioral mechanisms are critical for maintaining a stable body temperature.

Behavioral signs to look for:

Drinking more water than usual
Eating less than usual
Less active than usual
Sitting or lying with wings spread out
Panting
Seeking out cooler areas, such as lying underneath drinkers
Isolating themselves or moving away from other birds in the flock

Reducing risks of heat stress

Poultry should have access to fresh, clean and cool (not frozen/hot) water at all times
Increase air flow and ventilation
Provide shaded areas for poultry kept outdoors
Reduce stocking density in warm and hot weather (provide more space per bird)
Reduce additional stress on birds if possible, such as catching, loading and transporting
If birds do need to be caught and transported, plan to do these activities during the coolest parts of the day
Make sure all workers are trained to recognize and monitor birds for signs of heat stress