Constructing top-class poultry houses is important if you want to achieve the best possible production quality. Providing a healthy and comfortable environment will help you do so.

Adequate ventilation (or air-flow) in poultry housing is extremely important for chicken health. But you have to get the ventilation right so that it doesn’t create a draught. The actual main aim is to regulate the temperature within certain limits, bring in oxygen and remove moisture and toxic gases from the chicken house.

REGULATING TEMPERATURE

The temperature in chicken houses varies as heat is produced by the chickens and enters the house through the roof and walls. Chickens are warm-blooded (Homeothermic) and can maintain a uniform temperature of their internal organs by producing heat within their metabolic processes. This is only possible when the ambient temperature is constant.

A good rule of thumb is to ensure the ambient temperature in houses for adult chickens remains between 17 and 25°C. For smaller chickens, maintain a temperature between 22 and 37°C.

How much heat is produced by the chickens depends on a variety of factors such as their type, gender and age, the caloric value of the feed and how active the chickens are.

In general southern Africa is a hot country, with plenty of sunshine. This means that poultry producers have to make provision for the fact that the majority of heat entering or exiting the house will be through the roof. How much this is, however, depends largely on the size, the type of construction, building materials and sun orientation.

Chickens will be much healthier if insulation is installed. Without it they will become either too hot or too cold and this can inhibit growth. In production set-ups where artificial heating and cooling are used, insulation will help save energy and electricity costs in the heating process.

Good airflow is also a tool to control temperature. If the temperature is too low and has to be increased, the airflow through the house will have to be minimised. If the temperature is too high and has to be decreased, the airflow through the house will have to be increased.

One of the simplest ways to manage airflow is by using curtaining – either open or close the curtains, depending on how much air is needed. One of the common mistakes farmers make is not opening the curtains when it is cold. Even in cold weather, airflow is important to maintain sufficient oxygen.

HUMIDITY AND TOXIC GASES

The relative humidity inside chicken houses has to be between 30% and 75% (60% is optimum). If the relative humidity is too high, litter material will become wet and evaporative cooling will become very difficult. If the relative humidity is too low, respiratory diseases occur.

A farmer should also take precautions to prevent toxic gases building up in chicken houses. The most common gas is ammonia (NH3). A “nauseating smell” or an eye irritation indicates that the ammonia concentrations are too high.

In chickens, continuous high ammonia concentrations reduce the cilia in the respiratory tract and have a negative impact on growth and egg production.
Also ensure that there’s enough oxygen and fresh air in the houses. If toxic gases, especially carbon dioxide, are not removed and the level reaches more than 10 000 ppm, the chickens will suffocate.

MORE CONSTRUCTION TIPS

• Don’t use wood to build poultry houses. Wood cannot be disinfected and will compromise hygiene. Rather use corrugated iron.
• Make sure that your poultry houses are secure to prevent stock theft. How much security, and the type, depends on your budget.
• A durable fence is adequate to secure the property. Individual chicken houses can be secured using a padlock.
• Another good way to keep intruders away is to install good lighting on the property. Make sure that lights shine away from the chicken houses.

This article was first published in the book: Guide to poultry production, published by Landbouweekblad.