Heat Stress in poultry – what are the signs and how can we combat it?

I’m sure many people across the UK have been enjoying the beautiful weather recently, which has been welcomed and made it a little easier to remain in our gardens following social distancing restrictions. The same cannot be said for the poultry industry – as the months become hotter and we venture into the peak of summer, heat is a real problem for poultry.


The poultry industry is heating up…

Poultry sheds become a very warm environment very quickly in the Poultry sheds become a very warm environment very quickly in the summer, which can have detrimental effects upon the birds they house. Without good ventilation or cooling methods, the high humidity together with high temperature in chickens houses can cause huge distress to the birds inside. Large scale farms tend to have temperature controlled houses, however these can fail and lead to mass deaths as observed in Lincolnshire in July 2019, where temperatures reached a whopping 38°C after the temperature alarm failed to alert staff (Read about it here). Smaller producers may not have the luxury of temperature controlled sheds and try to manage birds as best they can. Unfortunately meat chickens (broilers) already produce an excessive amount of heat, so this only exacerbates the problem. Heat stress also has an impact on laying hens, impacting egg quality.


Heat Stress

If the heat is not fatal, excessive heat or prolonged periods of heat can lead to heat stress of the bird. Heat stress activates the HPA axis in the bird, leading to raised levels of corticosterone which is used to clinically define heat stress. This is also accompanied by upregulated expression of Heat Shock Proteins (HSP).  Additionally behavioural signs of heat stress are observed in parallel, such as:

  • Panting
  • Prostration
  • Increased respiratory rate
  • Spreading of wings
  • Squatting/low to ground
  • Reduced feeding
  • Increased drinking/resting

Apart from being a huge concern for welfare, heat stress can lead to a reduction in body weight gain and impact upon immunity and metabolism (Lara L 2013) leading to a potentially large economic loss for producers. With this in mind, some producers choose to supplement their poultry to try to counteract the negative effects of heat. For example, supplements to increase weight gain to make up for the loss in productivity and minerals to support the immune system, ensuring good health and fewer deaths observed. 


What can RRL do?

Unless things change, the  inevitability of global warming will see temperatures creeping up still in the summers to come, so poultry farmers must find a solution. This upcoming market for heat-stress supplements with an aim to reduce the economic loss caused by heat and improve welfare may be one to keep an eye on. 

At RRL we have a bespoke temperature and humidity controlled facility  which can mimic the environment in a chicken house on a hot summers day.  These facilities have been designed to test the efficacy of heat-stress supplements and thus to enable efficacious products to improve the poultry economy and welfare of animals. Alongside this we have been developing methods using observation of  heat stress associated behaviors to use as non-invasive measures of the degree of heat stress. 

For more information, please visit our CRO page to read more about the services we offer.

For enquiries regarding heat-stress studies or anything else please contact us using our contact form here, send us an email to enquiries@ridgewayresearch.co.uk or give us a call on +44(0)1594530809.