POULTRY · OWNER EDUCATION
Infectious Bronchitis in Chickens
Infectious bronchitis is a contagious coronavirus disease of chickens. It mainly affects the respiratory tract, but some strains damage kidneys or egg production; it is not the same virus as human COVID-19.
THE SHORT VERSION
What matters for your animal?
Start with the warning signs and when-to-contact sections if your animal is unwell. The same outward change can have several causes, so this guide helps you prepare questions rather than identify a diagnosis on your own.
What is this condition?
Infectious bronchitis is a contagious coronavirus disease of chickens. It mainly affects the respiratory tract, but some strains damage kidneys or egg production; it is not the same virus as human COVID-19.
Infectious bronchitis can affect more than the sound of a chicken's breathing; the flock pattern and changes in production can be relevant. Similar respiratory signs occur with other poultry diseases, so confirmation matters. Record how many birds are affected, when illness began, and recent introductions. The response needs to consider the flock and biosecurity as well as support for visibly ill birds.
Which species does this guide cover?
The species listed above are the focus of this guide, rather than a complete list of every animal that can develop this condition. Causes, testing and treatment may differ between species and individual patients.
Why can it happen?
- Virus spreads through infected birds and contaminated equipment. Young birds and inadequately protected flocks are vulnerable.
An infectious illness depends on both the organism and the animal's ability to resist it. Exposure does not always produce the same severity of illness in every animal. Age, previous immunity, nutrition, stress, and concurrent disease can influence the outcome. The infection may also cause complications that need treatment separately from the organism itself. For example, correcting fluid loss or supporting breathing can be essential even when a targeted medicine has already been started.
What might an owner notice?
- Coughing, sneezing, noisy breathing, reduced growth, fewer eggs or misshapen eggs. Kidney involvement can alter droppings and water intake.
Breathing effort is often more important than the sound an animal makes. Watch for increased work of the chest or abdomen, an unusual posture, inability to settle, or a change from that animal's normal pattern at rest. A quiet animal may still be struggling. If breathing is difficult, repeated handling can add stress and worsen the situation. Contact the appropriate veterinary service promptly and follow transport instructions rather than spending time trying to identify the cause at home.
The number affected and the sequence of cases can provide important clues. Record which animals or colonies changed first, whether they share feed, water, housing, equipment, or recent contacts, and any deaths. One patient's improvement does not establish that the shared cause has been removed. A group investigation may require different samples or visits from the care of one visibly affected animal. Avoid moving animals or materials between groups while a potentially transmissible problem remains unresolved.
How is the problem investigated?
Flock history and laboratory testing help distinguish it from other respiratory diseases. Examination of affected or recently dead birds may be important.
Molecular testing, such as PCR, looks for genetic material from a target organism in the submitted sample. It can be useful, but the meaning depends on the sample site, timing, and disease. Detecting material is not always the same as proving that the organism explains every sign, while a negative result may not exclude infection if sampling or timing was unsuitable. The veterinarian interprets the result alongside the examination and other findings rather than treating it as an isolated verdict.
What might treatment involve?
Supportive flock management addresses ventilation, temperature and hydration. Antibiotics do not cure the virus but may be used for confirmed secondary bacterial problems.
This is an overview, not a prescription or a recommendation for a specific individual animal.
What can owners do at home?
Limit flock movement and follow sampling and cleaning instructions. Record daily egg production, illness and losses.
Avoid actions that could make care less safe.
- Do not introduce new birds during an outbreak or treat every respiratory illness with the same antibiotic.
What can the longer-term outlook involve?
Outcome depends on strain, age and complications; egg production may not fully return to its previous level.
Can risk be reduced?
A flock-specific vaccination and biosecurity plan is more useful than an unsupervised universal schedule.
Disease prevention includes the route by which animals, people, equipment, bedding, feed, or water can carry a problem between groups. Separation works best when it also includes dedicated tools, careful handling order, and an appropriate cleaning plan. A newly arrived animal may appear well while a disease is incubating. Ask which tests or observation period suit the species and suspected disease before mixing groups. Cleaning, disinfection, and disposal requirements differ between organisms, so a single household product is not a universal solution.
When should you arrange care?
- Seek immediate veterinary advice for rapidly increasing illness, breathing difficulty or multiple deaths.
Seek urgent veterinary advice if you notice:
DO NOT DELAY URGENT CARE- Seek immediate veterinary advice for rapidly increasing flock illness, breathing difficulty or multiple deaths.
What information helps the care team?
Record actual food intake, weight changes, droppings, enclosure conditions and recent introductions. A photograph of the enclosure and the exact diet and supplement labels can help reveal factors that are difficult to see during the appointment.
How should you understand the tests?
Ask what each proposed test is intended to answer. Some tests identify a cause; others assess severity, organ function or treatment safety. Results are interpreted with the examination and history. A normal result does not exclude every problem, and an abnormal result does not always explain every sign.
Questions to ask before leaving
- What is confirmed, and which other explanations are still being considered?
- What changes should we expect with the proposed plan, and when should we reassess if they do not occur?
- Which observations should I record, and which changes mean I should call sooner?
- What medicine or home-care problems should I report, and what are the instructions for a missed dose or suspected side effect?
- When is the recheck, what will it assess, and whom should I contact after hours?
A care plan may be adjusted as results or the response become clearer. Keep the written instructions and tell the team if cost, handling or administration difficulty makes the plan hard to follow.
Sources behind this guide
Infectious Bronchitis in Chickens - Poultry - Merck Veterinary ManualVeterinary, university or animal-health guidance ↗Content last reviewed: October 3, 2026. Review status: veterinary-informed; independent veterinarian review not yet completed.