Poultry House Ventilation and Respiratory Disease
Many respiratory disease cases on Egyptian poultry farms do not start with a new infection but with poor ventilation that makes birds more vulnerable to organisms already present in the house. Ammonia, dust and high humidity damage the cilia lining the respiratory tract, so birds lose their first line of defence. The result is repeated respiratory disease, weak vaccine response and summer deaths driven by heat stress combined with poor airflow.
Ammonia: the hidden enemy
Ammonia comes from the breakdown of uric acid in droppings and rises when litter is wet, airflow is weak and stocking density is high. At low levels it begins damaging cilia; at higher levels it inflames eyes and trachea. Birds do not scream about ammonia, but they suffer repeated respiratory disease and grow slowly.
Measure at bird head height, not at the house door, because the gas is heavier than air and concentrates low down. Your nose is not an accurate instrument; use a meter or detector strip. If your eyes sting when you walk in, the birds are living well above the safe level. Record the reading twice a day in a fixed log so houses and cycles can be compared.
Humidity, temperature and real demand
Relative humidity should normally stay between 50 and 70 percent. Higher humidity stops water evaporating from litter and increases ammonia, while very low humidity raises dust and dries mucous membranes. In the Delta summer, temperatures reach levels that make birds pant, increasing water loss and disturbing blood acid balance.
Temperature alone is not enough; what matters is the heat index created by temperature, humidity and air speed. A young chick needs more warmth, while a heavy bird near market age produces heat and needs cooling. Ventilation settings should therefore change with bird age, not only with the season.
Tunnel and minimum ventilation
In summer, tunnel ventilation uses fans at one end and inlets at the other to push air fast over the birds and cool them by convection. The right air speed depends on age and weight, and excessive speed also causes stress. The house must be sealed and unused openings closed so air follows the intended path.
In winter the system relies on minimum ventilation in short cycles to remove humidity and ammonia without chilling birds. Ceiling or side inlets distribute cold air away from the flock. The common mistake is sealing the house completely in winter, which lets ammonia build and brings respiratory disease within a week.
- Read ammonia at bird head height in the morning before opening the house.
- Fix drinker leaks immediately because water on litter means ammonia.
- Keep a daily record of temperature, humidity and air speed.
- Clean curtains, fans and inlets of dust every cycle.
- Never seal the house fully in winter; use short ventilation cycles instead.
Linking ventilation to vaccines and disease
Birds living in poor air respond weakly to vaccines because their respiratory tract is already inflamed. High ammonia also reduces the effectiveness of spray vaccines, damaging the vaccine virus or blocking its contact with the mucosa. Improving air quality two days before vaccination is a simple step with a large effect.
Combined respiratory disease is usually a mix of Mycoplasma, E. coli and virus, and ventilation decides how severe it becomes. Accurate temperature and humidity monitoring catches problems early, such as with a digital thermometer. Suitable water and ventilation equipment is in our poultry supplies, and immune support with poultry vitamins is used under veterinary supervision.
Conclusion
Ventilation is not a summer luxury but daily medicine. Low ammonia, controlled humidity and air moving along the right path protect the respiratory tract and make vaccination work. Measure the numbers daily and consult your veterinarian when signs repeat.
This article is general guidance and is not a substitute for examining your animal by a licensed veterinarian. In emergencies, contact your vet immediately.
