Small-Flock Poultry

Another Coronavirus

COVID-19 has understandably dominated the news for most of 2020. While this particular strain, only identified in 2019, is relatively new, another coronavirus has preoccupied poultrykeepers for years, decimating chicken flocks around the globe. Better known as infectious bronchitis, chicken coronavirus is highly contagious and affects adult birds, as well as young birds. Read on to learn more about this lethal illness so you can recognize it should it strike your flock.

Symptoms

The signs of infectious bronchitis differ depending on the age of the afflicted chicken. Mature layers experience a drastic decrease in egg production. You’ll see an approximate 50% drop, according to veterinarian Richard M. Fulton, a professor at Michigan State University’s Veterinary Diagnostic Laboratory. Eggs lain tend to be severely misshapen with very thin whites.

Furthermore, a hen infected with infectious bronchitis during the first two weeks of life will develop blind layer syndrome, in which her oviduct is either partially or completely absent. A blind layer will still ovulate, but the ova pass into her body cavity. This causes her to have a swollen, droopy, fluid-filled abdomen and a waddling gait. In young chickens, coronavirus has more recognizable respiratory symptoms: cough, mucus and rattling/clicking in the throat.

Internal Signs

Although the symptoms of chicken coronavirus are visually recognizable, the damage caused by the disease is far more extensive. However, it tends to go unnoticed until a postmortem examination.

A necropsy of an infectious bronchitis-infected bird typically shows blood-engorged vessels in the lower third of the trachea as well as accumulation of tracheal mucus. This makes it extremely difficult for the bird to breathe. Several strains of coronavirus affect the kidneys, causing them to become pale and enlarged. Uroliths, or bladder stones, tend to accompany these nephropathogenic strains. Gross lesions are frequently found in both the respiratory tract and oviduct. And the chicken’s nasal passages and sinus cavities commonly contain a liquid, phlegmy or cheeselike substance.

According to Fulton, younger chickens suffering from infectious bronchitis usually die from secondary

Symptoms of infectious bronchitis — an acute, highly contagious upper respiratory tract disease in chickens — can include decreased egg production and quality.