Temperature plays a vital role in broiler production. The broiler bird will not perform to its full genetic potential if it is not provided with the right temperature whether during brooding or in the older stage. The main objective in temperature management is to efficiently and economically provide a comfortable, healthy environment for growing birds.

Failure to provide a favourable environment during rearing will result in reduced growth and development, poor feed conversion and increased disease, condemnation of carcasses, and mortalities, thereby reducing profitability.

During brooding

This happens in the first 2 to 3 weeks of production. Temperatures must be regulated to provide an optimum environment for the chicks. Chicks during this stage are poor at regulating their body temperature, hence they require that an external heat source be provided. If the house temperatures are low, the chicks get chilled and stressed. If the environment is too hot, they become inactive and will spend most of the time laying down instead of eating. Use a thermometer and observe chick behaviour to ensure the temperature is kept within the chicks’ thermal comfort zone.

When chicks huddle together near a heat source, the temperature is too low. Provide more heat. If they stay far away from the heat source or move to the extremities of the room, then the pen is too hot. Reduce heat and drop the curtains to allow more cool air in. Chicks that are within their thermal comfort zone are spread out all over the pen, eating, drinking, sleeping, playing!

Regulating brooding temperature

During brooding, temperatures are kept at an optimum level by providing heating by way of infrared bulbs, gas burners, braziers et cetera. Follow the recommended daily temperature to ensure regulated heat, and reduce instances of temperature fluctuations in the brooder. Regulate the temperature within the pen by providing a balance between temperature and ventilation. Too much ventilation will cause the temperature to drop, and poor ventilation may result in increased temperatures within the pen. Balance the two to get the right temperature when dealing with either chicks or older birds.

Open curtains covering the windows from top to bottom and not from bottom to top. This will ensure a clear outlet for waste gases (carbon dioxide, ammonia, carbon monoxide et cetera) and a good inlet for fresh air. This is important because waste air that is warm will always rise to the top and find its way out through the opening at the top of the window. Then the cool air full of quality oxygen getting into the pen from the top gets warmed up on its way down before it reaches chick level.

Effects of low temperatures during brooding

Low feed and water intake translate into poor growth and development of chicks. Chilled chicks have a suppressed immunity, and therefore become susceptible to diseases resulting in high first week mortality. High mortalities occur due to chicks huddling together and crushing each other to death. If chicks do not eat or drink because they are chilled and uncomfortable, they will not digest feed and will not benefit from heat produced during the digestive process. The digestive tract is not stimulated, therefore its development is poor resulting in poor growth rates and low weights. The chicks will not take up the carbohydrates they require to absorb the residual yolk sac quickly. If the yolk sac remains unabsorbed, it increases the risk of navel yolk sac infections such as omphalitis, which will result in increased mortalities in the first week. The unabsorbed yolk sac has maternal antibodies that the chicks benefit from once they absorb it. If it is not absorbed, the chicks will not get the full benefit of the maternal antibodies. This may result in poor health.

Temperature management in older birds

Temperature management in older birds is also critical. Once birds get older, their body temperature range between 40 and 440C. The appropriate temperature in the house is between 13 and 250C. The birds are constantly losing heat to their environment. To keep them comfortable, provide a balance between their body temperature and the house temperature. If the house temperature is lower than the body temperature, the chickens will lose body heat and become cooler. When kept in a hot, poorly ventilated pen, the birds may overheat and suffer heat stroke. We need to keep them cool with lots of fresh air and good quality oxygen.

This can be achieved by the following activities:

  • Providing adequate ventilation wide open windows on either side of the house.
  • Using an appropriate stocking density with emphasis on environmental temperatures.
  • If the pen gets too cool, lift some curtains to reduce the draft entering to increase the temperature.

Results of poor heat regulation in older birds

If chicks are not kept in a cool, well ventilated pen, they may get heat stress and die due to heat stroke. The feather cover on older birds is more useful in heat retention and not heat loss when the ambient temperature is too high. Help the birds cool off by providing a cooler environment. Overheated birds will drink more water to cool themselves at the expense of feed intake resulting in delayed growth.

If temperatures are too low, the birds will consume more feed and use much of it to convert into body heat through the digestive process. High temperature resulting from poor ventilation will cause poor litter quality leading to build up of ammonia, outbreak of diseases and skin lesions on the bodies of the birds.