For chickens, humidity also plays a role when they start suffering from heat stress. The higher the air humidity in the barn, the sooner the chickens will suffer from heat stress. Normal body temperature is around 41.5°C. If their body temperature reaches 44°C, the chicken will die.

Chickens with hear stress suffer from the follow symptoms :

  • Chickens sit with their beak open.
  • Chickens have an increases respiration rate.
  • Low wing tension.
  • Chickens have an increased water intake.
  • Chickens have a lower feed intake.
  • Chickens keep their wings extended so they can release the heat.
  • Chickens can suffer from heart problems due to increased pH value in the blood.
  • The eggs are smaller.
  • The quality of the eggshell decreases.
  • Production decrease.


At stable temperatures up to about 30 degrees, a hen can release her body heat to the environment by spreading its wings. Above 30 degrees in the barn, the breathing frequency increases and the hen will breathe with its beak open. This causes too much carbon dioxide to be exhaled, which lowers the carbon dioxide levels in its blood and raises the pH value.

  • Salt also evaporates from the beak, causing a salt deficit in the blood.
  • When the humidity in the barn is too high, panting does not work for the hen either.
  • If the temperate stays too high for a period of time and the chicken suffers from heat stress, it will become increasingly weak until it finally dies.
  • Heat stress releases stress hormones into the chicken, causing its immune system to malfunction; making it more susceptible to disease.
  • Because of the increased pH values in its blood, there is less calcium in the blood, resulting in egg shells to become thinner and the quality of the egg to decrease significantly.
  • The chickens will move less, have a lower feed intake and will eventually lay fewer eggs of poorer quality.
  • As a result of heat stress, broilers will also grow less quality. Young hens have a lower weight and start laying eggs later. Parent birds have reduced fertility because they mate less.
  • The chickens will be slower, there is more drop-out and an increase in cannibalism.
  • When the barn temperature gets too high, chickens will die and there is a high dropout rate.
  • The effects of heat stress can last up to 6 weeks.


To prevent heat stress in your chickens, we work with fans and misting. We also use roof sprinklers on uninsulated roofs.

Chickens can suffer from heat stress if the temperature in the barn gets higher than 25 degrees. 

If the temperature becomes too high for the chickens, we will start to operate the fans and roof sprinklers, if applicable to your farm. If the temperature continues to rise, the misting will be activated. The misting works with a pulse pause system. The lower the temperature, the longer the pauses between misting. As the temperature rises, the pauses between misting become shorter and shorter. 

We always use a climate computer. This monitors the temperature inside and outside your barn and also the humidity inside the barn.

If the air humidity in your barn gets too high, for example just before a thunderstorm, the misting will switch off automatically. This is to ensure that your chickens and the house do not get wet.

Under products you can find more information about the pumps and fans we use.