Written by: Dr. Jacquie Jacob, University of Kentucky

Infectious bronchitis (IB), also referred to simply as bronchitis or a cold, is a virus that affects chickens. A similar disease can affect bobwhite quail (quail bronchitis), but it is caused by a different virus.

Infectious bronchitis is highly contagious and can spread quickly through a flock. The virus is spread through the air and on feed bags, infected dead birds, and rodents. The virus can also be transmitted through the egg to developing embryos, but an affected embryo typically does not hatch.


The severity of infection is influenced by the age and immune status of the flock, by environmental conditions, and by the presence of other diseases in the flock. The list that follows describes some of the signs of infectious bronchitis:

  • Consumption of feed and water declines.
  • Sick chickens chirp and have watery discharge from the eyes and nostrils.
  • Young chickens have labored breathing and might gasp. Breathing noises are more noticeable at night while the chickens are resting.
  • Egg production among laying hens drops. (Production should recover in five to six weeks, but it will remain lower than previous levels.) 
  • The infectious bronchitis virus can infect different parts of the body, including the reproductive system. When a hen’s reproductive system is infected, the shells of the hen’s eggs can become rough and misshapen, and the egg whites can become watery.


There is no specific treatment for infectious bronchitis. Administering antibiotics for three to five days may aid in fighting off any secondary bacterial infections. For brooding chicks, it is helpful to raise the room temperature 5°F until symptoms go away.


An effective biosecurity program is the best method of preventing infectious bronchitis. Such a plan should include rodent control. Vaccinations are available.


Overview of Infectious Bronchitis in poultry. Merck Veterinary Manual.