Why ventilation is key in poultry rearing

Poor ventilation is a leading cause of respiratory distress on poultry farms, and it often goes unnoticed until serious damage has already occurred.

In a poorly ventilated house, harmful gases and dust build up, creating an unhealthy environment for the birds. Among these gases, ammonia is the most common and problematic.

Ammonia is produced when uric acid in poultry droppings breaks down into urea.

The white part you see on top of chicken droppings is uric acid.

When litter becomes too wet—due to high humidity, poor airflow, leaking drinkers, poor-quality feed, or diseases that cause diarrhoea—ammonia levels rise.

High ammonia levels have a direct negative effect on bird performance.

In broilers, it slows down growth and reduces feed efficiency, meaning birds eat more feed but gain less weight.

For layers, poor ventilation and high ammonia levels can reduce egg production, especially in severe cases.

Birds exposed to ammonia may start showing signs such as sneezing (snicking), abnormal breathing sounds (tracheal rales), red or irritated eyes, and inflammation of the air sacs.

In advanced cases, they may develop pneumonia, lose eyesight, or even suffer from burns on their feet and breast, leading to lameness and carcass rejection at the market.

Another gas to watch out for is carbon dioxide. This gas is naturally produced by birds during breathing, but it becomes a problem when it builds up in poorly ventilated houses.

During brooding, carbon dioxide levels can rise quickly, especially when farmers use charcoal or other fuels that consume oxygen and release CO₂.

Using airtight materials such as polythene curtains without allowing fresh air in can be very dangerous and may even lead to the sudden death of chicks. Even during brooding, it is important to allow some fresh air into the house.

Carbon monoxide is even more dangerous, as it is highly toxic and can kill birds within minutes.

It is produced when fuel does not burn properly, often due to faulty or poorly maintained brooders.

When inhaled, carbon monoxide replaces oxygen in the blood, leading to poisoning.

Too much dust

Birds affected may appear weak, drowsy, and uncoordinated and have difficulty breathing. Their tissues may appear unusually pink.

To prevent this, ensure brooders are well maintained, avoid yellow flames (which indicate incomplete combustion), and always allow proper ventilation, even in cold weather.

Dust is another hidden danger in poultry houses. It comes from feathers, litter, feed, and manure.

When birds inhale too much dust, it damages the lining of their respiratory system, making it easier for diseases caused by bacteria, viruses, mycoplasma, and fungi to develop.

Dust can also cause eye irritation and skin inflammation. Over time, this leads to poor growth, low feed efficiency, and higher mortality rates.

To avoid all these problems, proper ventilation is essential. Farmers should regularly open curtains to allow fresh air in and remove stale air.

If natural airflow is not enough, using fans can help improve air circulation.

At the same time, stocking density must be well managed. Overcrowding makes ventilation less effective and increases moisture and heat in the house.

For broilers in open-sided houses, aim for about 12 birds per square metre, and avoid exceeding 17 birds per square metre.

For layers, provide enough space, around 500 cm² per bird, to ensure comfort and productivity.

Good bird welfare goes hand in hand with proper management.

When birds are kept in the right conditions—with adequate space, fresh air, clean water, and quality feed—they grow better and produce more. Poultry farming is most profitable when farmers focus on creating the right environment.

This includes proper brooding, good ventilation, high-quality chicks from reliable sources, strong biosecurity measures, and a well-planned vaccination programme.

When all these factors are in place, farmers can achieve better performance and maximise returns on their investment.

Dr Messo is the company veterinarian, Kenchic