If my sneezing chicken doesn’t have bird flu, what is wrong with her?

by Dr Dyer BVSc

As of 8/9/26 there are no recorded incidences of H5 Bird Flu in pet birds or poultry in Australia. The situation is fluid and any backyard chooks showing signs (https://www.nsw.gov.au/regional-and-primary-industries/biosecurity/bird-flu)  should prompt a call to the disease hotline ( Emergency Animal Disease Hotline 1800 675 888 ).
 
But if your sneezing chicken doesn’t have Avian Influenza, what else could it be?
 
Five common underlying causes of respiratory symptoms such as wheezing, sneezing, weepy eyes and head swellings, in backyard chickens in NSW are:
 
1. Fowl cholera. Caused by Pasteurella bacteria.
2. ILTV/Infectious Laryngotracheitis Virus. Caused by a herpesvirus.
3. IB/Infectious bronchitis. Caused by a coronavirus. (not THAT coronavirus!)
4. Infectious coryza. Caused by Avibacterium.
5. Mycoplasma. A small, bacteria-like pathogen that weakens the host and makes them susceptible to other respiratory infections including psittacosis, aspergillosis, E.coli and Salmonella infections.

Where do these diseases come from?
Chickens, turkeys, and ducks who have had a fowl cholera infection in the past, and remain silent carriers, or who have been recently infected but have shown no symptoms, can be the biggest spreaders. Your older hens may look fine, but when you introduce new pullets, the young birds get sick.

Alternately, young birds with no symptoms can spread fowl cholera to the older members of your flock. The “all-in, all-out” system, where your flock consists of similar-aged chickens, and you don’t add any unless you lose all of your existing birds, can simplify your quarantine measures. We recommend you don’t mix chickens with turkeys or waterfowl for the same reasons.

Wild birds can also be a source of fowl cholera, contaminating the environment with mouth, nose, and eye secretions. Pasteurella can survive in the environment on shoes, clothes, and feed bags. ILT is not in wild birds but can be spread from other poultry in feathers and dust, on vehicles and equipment. IBV, in chickens only, spreads in droppings and in secretions from the mouth and nostrils by contact or in contaminated water or food. Older chickens are more susceptible to coryza, spread by direct or indirect contact, usually from carrier chickens.

How are they diagnosed?
Pasteurella, Mycoplasma and ILT can be diagnosed by sending laryngeal swabs to the NSW DPI for PCR testing. Unfortunately IBV is more often diagnosed on post-mortem by sending away tissue samples from birds that have died. PCR testing for coryza is from an infraorbital sinus sample, but the availability of this test varies. Bacterial culture of gram-negative Avibacteria from a lab sample may be possible, and this cause is one of the most likely to respond to antibiotics.

​But don’t forget that your substrate (whatever material is on the floor of your coop), allergens, vitamin A deficiency (not enough fruit and veg!), bushfire smoke, and heat stress can also cause respiratory signs. It’s not easy being a chook! But their quirky personalities are a delight to behold. May your chooks not dig up too many of your flowers this spring.