How Heat Stress Affects Poultry Performance

Heat stress is a major challenge in poultry production, with the potential to reduce performance and cause significant economic losses.

Modern poultry strains are more susceptible than previous strains because they have been selected for high rates of weight gain and egg production. This creates a greater metabolic load, making it harder for birds to cope when temperatures rise.

In broilers, heat stress can reduce feed intake and liveweight gain, while feed conversion may increase. It is also linked with higher mortality and poorer overall flock performance. Laying birds can be affected, leading to reduced egg production.

The effects of heat stress go beyond lower feed intake. Heat stress stimulates the production of hormones such as corticosterone. This can increase muscle breakdown and reduce protein accretion, affecting growth and meat quality.

Oxidative stress can also damage unsaturated lipids within the bird, with possible implications for meat quality and keeping quality.

The protective barrier function of the digestive tract can also be impaired. This is often described as “leaky gut”, where the intestine becomes more permeable to mycotoxins and harmful bacteria, including Salmonella species. 

This means heat stress can affect bird health, nutrient utilisation, growth, and product quality simultaneously.

Water intake is another important consideration. As temperatures rise, birds drink more to remain hydrated and reduce their body temperature. However, if water quality is poor, water is contaminated, or it becomes too warm, heat-stressed birds may reduce their water intake, increasing the risk of dehydration.

Cool, clean and readily available water is one of the most important practical measures during hot weather. Water consumption should be monitored closely, and drinker systems should be checked to make sure birds have consistent access throughout the shed.

Electrolytes and key vitamins, including vitamins C and E, can also be supplied through the water where appropriate to help birds cope with warm conditions and maintain performance.

Litter management can make a difference, too. Older, thicker litter tends to retain more heat, adding to temperature build-up within the shed. Replacing old bedding with fresh litter can help create a cooler environment for the birds.

Feeding times should also be reviewed. Offering feed during the early morning and evening can encourage birds to eat during cooler parts of the day and avoid the most intense heat.

These measures are simple, but together they can help reduce the pressure placed on birds during prolonged warm conditions.

Increasing fat inclusion is a common nutritional strategy during heat stress. Fat has a lower heat increment than carbohydrate or protein, meaning less heat is generated as the bird digests and uses it. This makes fat a useful way to increase the energy density of the diet when feed intake is under pressure.

Inclusion levels of up to 5% are known to provide positive benefits. Increased fat can help maintain energy supply, slow the rate of digestion, and improve the utilisation of other nutrients. The choice of product should still be based on the bird’s needs, the production stage, and the wider ration.

UFAC’s poultry range includes products designed to support energy density, omega-3 supply and mycotoxin management.

Megajule is a blended fat supplement developed to optimise energy supply in monogastric diets, making it relevant where greater energy density is needed as feed intake comes under pressure.

Omega 3 Supplement for Monogastrics and algi40 provide sources of omega-3 fatty acids and can support wider nutritional objectives around health, growth and production.

Mycotrap is a broad-spectrum mycotoxin adsorbent. This can be particularly relevant where heat stress has placed additional pressure on the protective barrier function of the digestive tract.

There is no single solution to heat stress in poultry.

Maintaining performance depends on combining good shed management with cool, clean water, appropriate feeding times and a ration designed to protect nutrient supply.

Fats can play an important role by increasing energy density while generating less heat during digestion than carbohydrates or proteins. Alongside appropriate electrolyte, vitamin and mycotoxin management, this can help support bird health, feed efficiency and overall flock performance.

UFAC’s expertise in fat and fatty acid nutrition helps feed manufacturers and poultry businesses select practical nutritional solutions for periods when hot weather places birds under additional pressure.