Poultry production: Ventilation – what works best?

A naturally ventilated chicken house uses wind to control airflow and mechanically ventilated houses control it electronically. The only question is which one will be suitable for your production system and budget.

Natural airflow

It can be more difficult to manage airflow naturally within a chicken house, but it is much more cost-effective. For natural ventilation to work, chicken houses have to be constructed in such a way that wind can be used to create airflow.

When constructing the house, take into account the position of the sun and the direction of the prevailing wind. The best way to do so is to make sure the open side of the house faces the direction of the predominant prevailing winds.

Using natural ventilation requires being very observant of external temperature, as too cold or too hot conditions can be detrimental to production.

The effective use of curtaining is one way to ensure good ventilation in houses. In addition to curtaining on the outside of the house, farmers should also put up a curtain on the inside wall. This will eliminate any draughts coming in through air vents that aren’t completely sealed off.

Farmers will quickly notice if there’s a draught: chickens tend to congregate on a side of the house that’s less exposed to unfavourable ventilation. Do not judge the ventilation conditions and temperature while standing.

If you’re standing upright inside the chicken house it usually feels warm, but even if it feels hot higher up, it could be cold lower down, on the floor.

If airflow has to be increased, farmers can use electric standing fans or industrial roof fans. It’s important to position the fans correctly or they could just blow hot air around without expelling it.

Position the fans as follows: open the curtains on both sides of the house and place a fan on one side facing the other open curtain. In this position, the fans will remove heat effectively.

Poultry producers in very hot areas should also take steps to keep their chicken houses well ventilated and at the right temperature. It’s a good idea to wet the roof – even if it’s been insulated – when it is very hot. Always try to reduce or remove heat at the source of the problem; and that is usually the roof. Use a garden hose to run water over the roof or use sprinklers.

The interior of the chicken house must be free of any obstruction, such as solid partitions, which prevent air from flowing naturally throughout the house.

Mechanical airflow

Mechanical ventilation reduces the need for constant monitoring and it makes it easier to control temperature and relative humidity. The system is also more reliable as it doesn’t depend on wind.

But farmers should have a standby generator on site in the event of a power failure. And if they can afford it, they could install an electrically controlled ventilation system.

Some farmers use probes installed on both sides of each house to monitor temperature. The probes hang half a meter above the chickens. Based on the temperature reading, the fans come on and off to create airflow as needed.

Farmers have a choice of three types of mechanically ventilated systems. The most common method is to extract air by using fans in chimney-like shutters near the ridge of the roof.

The second is called reverse ventilation. The air enters at the ridge and is extracted along the wall by means of fans. This system is much more expensive and it is essential that the ridge be correctly designed to prevent draughts of cold air.

The third system is mechanical cross-ventilation – once very popular for broilers and breeding houses. It’s an effective method for buildings having a span of up to 13m. But there is little or no ventilation during power failures.

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

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