How to control heat stress mortality in broilers

Broiler production has increased tremendously in the last 10 years, thanks to an increasing demand for product quality and food safety at an affordable price.

Most of our farmers grow these birds in open-sided housing system, which in hot environment is not always easy. Farmers keeping commercial broilers find it difficult to achieve maximum performance from these birds during heat stress period.

The feed conversion ratio, i.e., kilogrammes of feed required to produce one kg of live weight is more than 1.7kg (the lower the better) increasingly become unattainable during hot climates.

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Mortality rates also tend to increase especially towards cropping due to sudden death caused by heart failure as birds struggle to keep cool.  

Optimal temperatures generally stimulate activity and increase appetite of the birds, however high temperatures will result into lethargy, birds avoid feeding, they tend to drink excessive water which results into wet litter and loss of essential minerals from the body and hence dehydration.

Here are 6 solutions that farmers can apply to keep these bird’s performances top notch during hot periods.

1. Ideal housing structure

An ideal broiler house should be rectangular; it should be constructed on an east-west orientation to minimised or alternatively put a false ceiling made of gunny bags to absorb heat radiation from the roofing material.

Roof over hangs should be elongated to prevent direct sunlight hitting the birds on the open sides and a roof ridge with narrow outlets on the tip of the roof ridge will allow escape of hot air from the floor.

Please avoid flat roof if you can, they tend to hold warm humid air around the birds, which is difficult to evacuate.

2. Establish minimum ventilation

Minimum ventilation is important throughout the broiler growing and finishing periods, this is specifically to manage house temperature and humidity and to ensure air quality is good and freshly supplied frequently and at consistent intervals.

In extremely hot environment, I have advised the use of vertical fans mounted in the middle of the unit, they create horizontal air movement that has some chilling effects on the chicks. In environmentally controlled units, these fans are placed on the far end of the units to create tunnel ventilation that helps cool the unit.

3. Establish a good stocking density:

In most ideal situation, farmers would love to maximise utility of their unit, however during hot weather, it is only prudent that we reduce the stocking density of the birds to cope with the high temperatures.

This will help create more feeding and drinking space and allow quick dispensation of heat generated from adjacent birds.

4. Feeding under hot temperatures

During hot weather like we have at this time of the year, I would recommend entirely the use of crumble and or pelleted feed forms as opposed to mash diet.  

This will minimise the energy the bird will expend in feeding and likewise generate less energy during feeding. The feed intake will be high as birds will take less time filling the gut on crumbled forms compared to mash.

Feeding should be restricted to the cool part of the day or be done at night.

5. Provide fresh cool water all the time

Birds should have unlimited access to clean, fresh good quality drinking water at all times. Most of our farmers use borehole water, have you checked the chemical composition of your water recently?

During hot weather, it is advisable to provide municipal water which has acceptable level of minerals and organic matter. Provide sufficiently more access to cool water preferably at 15 degrees centigrade, this can be achieved by use of ice cubes in water, by painting outside of water tanks white to reflect sun rays and keep water cool.

6. Strategic application of vitamins

Strategic supplementation with commercial products rich in vitamins (A, C, D and E) and electrolytes like (sodium, potassium, and chloride) either in feed or in drinking water may help the birds deal with high environment temperatures.

Heat stress increases the bird’s excretion of these vital elements through fecal and urinary deposits and hence the need to replace the same in blood circulation.