Infectious bronchitis: why it affects both breathing and egg quality

Infectious bronchitis in poultry is one of the most common diseases in chicken coops worldwide. It is a highly contagious viral disease that primarily affects the respiratory system, but in many cases also causes significant damage to the reproductive system of the laying hen. This combination causes a decrease in egg production and quality, making the disease a significant economic problem in the laying industry.

The cause of the disease

The disease is caused by a virus from the coronavirus family (Avian coronavirus).

The virus is characterized by the ability to:

   •   spread rapidly in the chicken coop

   •   to mutate and create new strains

   •   to damage several systems in the chicken's body

For this reason, sometimes existing vaccines do not fully protect against all strains.

Respiratory tract damage

The name of the disease comes from the initial damage to the respiratory system.

Typical signs include:

   •   Coughing and wheezing

   •   Shortness of breath

   •   Nasal discharge

   •  Decreased feed intake

In young chicks, the disease may also cause increased mortality and stunted growth.

Damage to the reproductive system

The virus can also reach the hen's reproductive system, especially when infection occurs during the early laying period.

The damage can be in several areas:

   •   Ovary

   •   Oviduct

   •   Sheath-forming glands

The result is a decrease in egg production and sometimes irreversible damage to the laying system.

Impaired egg quality

One

of the most noticeable symptoms in infected laying hens is a change in egg quality.

You can see:

   •   Thin or rough shells

   •   Mortified eggs

   •   Decreased egg weight

   •   Watery albumen

Sometimes even after the flock recovers from the disease, egg quality does not return to its original level.

Transmission

The virus spreads very easily in crowded poultry houses.

The main transmission routes are:

   •   Respiratory secretions

   •   Direct contact between birds

   •  Contaminated equipment and clothing

   •   Polluted air in the poultry house

Due to the high rate of infection, the entire flock is sometimes infected within a few days.

Prevention and management

The main way to deal with the disease is prevention.

Important steps include:

Vaccination

   •   Live attenuated vaccine in chicks

   •   Boost vaccinations during rearing

   •  Adapting the vaccine to local breeds

Proper management of the coop

   •   Proper ventilation

   •   Reducing stress

   •  Preventing overcrowding

Biosecurity

   •   Disinfection of equipment and vehicles

   •   Limiting the entry of visitors

   •   Separation between flocks of different ages

Summary

Infectious bronchitis is a complex disease that affects multiple systems in the chicken body. Respiratory tract infection leads to decreased health, while reproductive tract infection leads to decreased egg production and quality.

Due to the high mutation rate of the virus and rapid infection rate, a combination of proper vaccination and strict biosecurity is key to reducing damage in commercial poultry houses.

*It is always advisable to consult a qualified veterinarian.