11 Aug 2025
Respiratory Diseases in Chickens – How to Protect Your Flock
Respiratory diseases are one of the most common and costly poultry health issues. They can spread quickly through a flock, reduce egg production, and cause long-term damage to bird welfare. Whether you keep a small backyard flock or manage a commercial layer shed, understanding the risks and signs of respiratory problems in chickens is key to protecting your birds.
Chickens have a unique and delicate respiratory system. Air travels from the nostrils, through the sinuses and trachea (windpipe), into the lungs and a network of air sacs – some even extending into the bones. This design helps chickens breathe efficiently, but it also means that infections can spread rapidly throughout the body once they enter.
Why Respiratory Health Matters in Poultry
Healthy breathing is essential for growth, feed efficiency, and strong egg production. When the chicken respiratory system is damaged by disease or environmental stress, birds may:
Eat less feed
Lay fewer eggs
Produce more misshapen or soft-shelled eggs
Lose weight
Become more prone to secondary infections
Even mild respiratory disease in chickens can cause production losses that take months to recover.
Common Causes of Respiratory Problems in Chickens
Respiratory disease can be triggered by:
Viruses – such as Infectious Bronchitis or Avian Influenza
Bacteria – including Fowl Cholera, Mycoplasma gallisepticum, and Infectious Coryza
Parasites – like Gapeworm
Environmental factors – dust, poor ventilation, high ammonia levels
Ammonia is a by-product of droppings breaking down in wet litter. At high levels, it irritates and damages the lining of the respiratory tract, making it easier for bacteria and viruses to infect your flock. If you can smell ammonia in the shed, it’s already too high.
Risk Factors for Poultry Respiratory Diseases
Poor ventilation or air flow
Wet litter from leaking drinkers
High stocking density
Introduction of new birds without quarantine
Contact with wild birds or contaminated equipment
Nutritional deficiencies, especially Vitamin A
Signs of Respiratory Disease in Chickens
Early detection helps prevent disease spread. Watch for:
Sneezing, coughing, or wheezing
Nasal or eye discharge
Swollen face or sinuses
Open-mouth breathing (“gaping”)
Rattly breathing (“rales”)
Drop in egg production or shell quality
Blue or purple comb/wattles (oxygen shortage)
Even if only a few birds are showing symptoms, respiratory diseases in poultry can spread quickly to the rest of the flock.
Preventing Respiratory Problems in Poultry
The best defence against chicken respiratory diseases is prevention:
Biosecurity – Control shed entry, clean boots and tools, prevent wild bird access.
Ventilation – Maintain fresh air flow without draughts; keep ammonia below 10 ppm.
Vaccination – Use a vaccination schedule suited to your location and flock type.
Nutrition – Ensure feed is balanced with all essential vitamins and minerals.
Daily monitoring – Walk the flock daily and record any signs of illness.
Why Some Poultry Diseases Are Harder to Control
Certain chicken respiratory diseases can remain in recovered birds for life, meaning they can still infect others. Others have no vaccine available in New Zealand, making strict biosecurity even more important. Free-range poultry systems face higher risks due to exposure to wild birds and weather-related stress.
Take Action Early
Ignoring early respiratory disease symptoms can lead to:
High mortality
Long-term production losses
Increased risk of other poultry health problems
Some respiratory diseases in poultry, like Avian Influenza, are notifiable — meaning a veterinarian must be contacted immediately if suspected.
