As the mercury rises in most of the Northern Hemisphere, we see people all struggling to keep cool. Unfortunately for animals, the luxury of air conditioning is one which they cannot afford. Poultry, being plumed animals, struggle to release heat from their bodies when environmental temperatures exceed their thermoneutral zones. Animals, housed in enclosed farm buildings with a high stocking density, also are highly susceptible to heat stress during these warm summer days.

Animals that experience heat stress attempt to compensate by eating and moving less, drinking more, and of course, panting and sweating. These behaviours naturally have a negative impact on growth, and lead not only to an increase in the feed conversion rate, but also have an adverse effect on animal welfare. Apart from eliciting heat stress modulating behaviours, prolonged heat stress also causes oxidative stress. This is due to the generation of reactive oxygen and nitrogen species by the bodily cells as well as a reduction in the natural antioxidant system’s functioning. This eventually causes a build-up of dangerous free radicals, leading to oxidative stress and subsequent damage to not only the important bodily cells, but also the immune system of the chickens. This results in lowered performance, and higher susceptibility to diseases due to the reduced integrity of the immune system.