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Western Small Flocks Collaborative

Infectious Bronchitis Virus (IBV)

Learn how IBV spreads, the signs to watch for, and steps you can take to protect your birds.

IBV Factsheet
Silhouette icon of a Infectious Bronchitis virus shape

Quick Facts

Silhouette icon of a Infectious Bronchitis virus shape IBV is caused by an avian coronavirus
Silhouette icon of a Infectious Laryngotracheitis virus infected chicken Spreads quickly, causes mild to severe illness in chicken flocks
Silhouette of pheasant Detected in gamebirds and peafowl, but this is rare
Silhouette icon of a dark brown human figure Does not spread to or infect humans
Silhouette of a boot with dirt on the sole and top Spreads through infected birds, contaminated surfaces, and respiratory droplets

What is IBV?

Infectious bronchitis (IBV) is a very contagious virus caused by an avian coronavirus. It mainly affects chickens and causes breathing problems. Some types of IBV damage the oviduct, which can cause a drop in egg production. Infected birds may also lay eggs that are pale, misshapen, soft, or wrinkled. The virus spreads through contaminated dust, droplets, and surfaces such as equipment, clothing, or litter. Birds of all ages can get sick. The virus changes often and birds can become infected more than once.

Silhouette icon of a brown caution symbol with an exclamation point in the center Infected birds can spread the virus for many months after infection.
Two eggs side by side each with a wrinkled shell
Eggs may be misshapen, thin, wrinkled, rough, pale, smaller than normal, and often have watery egg whites.

Signs of IBV

IBV is a viral respiratory disease that can look very similar to other poultry respiratory problems. Because symptoms overlap with conditions like infectious laryngotracheitis, avian influenza, Mycoplasma, infectious coryza, and Newcastle disease, testing is the only way to confirm IBV.

Respiratory signs:

  • Watery eyes
  • Runny nose
  • Sneezing and coughing
  • Rattly or noisy breathing

In laying hens:

  • Sudden drop in egg numbers
  • Poor shell quality: thin, wrinkled, or misshapen eggs
  • If young hens are infected, their egg system may not develop correctly. These birds can look normal but never lay eggs. Sometimes their belly swells, and they stand upright like a “penguin.”

Timing:

  • Signs can appear within 1–2 days after exposure
  • Individual birds often improve in 10-14 days, but the virus can keep spreading for weeks
Diagram of multiple signs of infectious bronchitis virus (IBV)
Common signs of IBV include watery eyes, nasal discharge, coughing, rattly breathing, loose droppings, reduced feed intake, misshapen eggs, and birds appearing tired or weak.

How does IBV Spread?

Contact with infected birds:

  • Sick birds spread IBV through saliva, nasal discharge, eye secretions, and droppings.
  • Birds may look healthy but can still carry and shed the virus.

Contact with contaminated surfaces:

  • The virus can travel on shared tools, feeders, waterers, boots, clothing, and bedding.
  • People can move the virus between flocks on their hands, shoes, or clothing.

Airborne spread:

  • IBV spreads quickly within a flock as birds breathe in droplets from coughing and sneezing.
  • Dust and dander in poultry houses can carry the virus short distances.
Silhouette of how IBV spreads between other fowl, water tank, environment and boots
Arrows show how IBV spreads: sick birds shed the virus in droplets and droppings, and it can also move on people’s boots, clothing, and contaminated equipment to infect healthy chickens.

How Do You Treat IBV?

  • No direct cure – IBV is a virus, so there’s no medicine to eliminate it.
  • Supportive care – Provide clean water, good feed, and reduce stress, drafts, and dust.
  • Prevent complications – Veterinarians may use antibiotics to control secondary bacterial infections.
  • Management – Isolate sick birds and strengthen biosecurity to protect other flocks.
  • Long-term effects – Most birds recover, but laying hens may not return to full production.

How Do You Prevent IBV?

Practice Biosecurity

  • Limit contact with birds from other flocks.
  • Wear coop-dedicated shoes to keep out germs.
  • Keep the coop, equipment, and your hands clean.

Separate New or Returning Birds

  • Isolate new or returning birds for at least 3 weeks and monitor for signs of illness.
  • Germs can spread before birds show signs.

Limit Visitors and Shared Tools

  • Require approved visitors to wear clean clothes and boot covers.
  • Minimize sharing tool or equipment.

Handle Healthy Birds First

  • Care for birds in this order: young → adults → sick, to avoid spreading germs.
  • Wash or sanitize hands and equipment between different bird groups.

What if IBV is Found in Your Flock?

Work with a Veterinarian

  • A veterinarian can help confirm the disease and guide next steps.
  • Ask your veterinarian if IBV vaccines are right for your birds.

Isolate Sick Birds

  • Separate sick birds from the flock to limit spread of the virus.

Don’t Spread Disease

  • Do not buy or sell birds during or after an outbreak.
  • Even healthy-looking birds can shed this virus for months after infection.

Confirm with Testing

  • Testing can identify the cause of illness and help guide your next steps.
  • Work with your veterinarian to coordinate testing.