Trichomonosis in Chickens: Mouth Lesions, Difficulty Eating, and Spread

Trichomonosis is an infection caused by Trichomonas gallinae, a microscopic protozoan parasite that most often affects the mouth, throat, esophagus, and crop of birds. In chickens, it can create inflamed tissue and thick yellow or yellow-white caseous plaques that make swallowing painful or physically difficult.

This disease is better known in pigeons and doves, where it is often called canker, but domestic poultry can also become infected. Chickens may pick up the organism from contaminated water or feed, especially when wild pigeons or doves have access to the coop, run, feeders, or waterers.

The biggest concern is not only infection itself, but what the lesions do. As the plaques enlarge, they can block the mouth or upper digestive tract. Some birds then stop eating, lose weight quickly, drool, or struggle to breathe. Young or weakened birds can decline fast, so early veterinary evaluation matters.

Trichomonosis is caused by the protozoan Trichomonas gallinae. The organism spreads mainly through fresh saliva, regurgitated food, and contaminated drinking water or feed. In backyard flocks, a common risk is exposure to infected pigeons and doves, which may carry the parasite without looking very sick.

Chickens can become infected when wild birds drink from shared waterers, peck at feeders, or contaminate feed storage areas. Wet, dirty equipment increases risk because the parasite survives best in moist material, even though it does not persist for long in dry environments.

Not every exposed chicken becomes severely ill. Disease severity depends on the strain of the parasite, the bird's age, overall health, and how much tissue damage develops. Young birds and birds already stressed by crowding, poor nutrition, or other illness may have a harder time coping.

Your vet will usually start with a careful history and oral exam. Visible yellow plaques can strongly raise suspicion, but they are not specific to trichomonosis. Other problems can look similar, including candidiasis, pox lesions, capillaria, vitamin A deficiency, bacterial infection, and some other causes of oral or crop plaques.

To confirm the diagnosis, your vet may collect fresh material from the mouth or throat and examine it right away under the microscope in saline to look for motile trichomonads. Depending on the case and what testing is available, they may also recommend cytology, culture, PCR, or necropsy if a bird has died.

Because these organisms are easiest to identify in fresh samples, timing matters. If a chicken dies, refrigeration is usually more helpful than freezing before diagnostic submission, but your vet or diagnostic lab should guide you on exactly how to handle the body.

Prevention focuses on biosecurity and sanitation. Keep pigeons and doves away from chicken feeders, waterers, and feed storage whenever possible. Raised or covered feeders, enclosed runs, and prompt cleanup of spilled feed can make a real difference.

Clean waterers and feeders regularly, especially in warm weather or if wild birds have been visiting. Cornell and Merck both note that a 10% bleach solution can be used to disinfect bird-contact surfaces such as feeders and baths after cleaning away organic debris. Let items dry fully before reuse.

If one chicken develops suspicious mouth lesions, separate that bird and contact your vet. Avoid sharing water containers between groups, and wash hands, boots, and equipment between pens. In a mixed backyard setting, reducing wild-bird contact is one of the most practical ways to lower risk for the whole flock.