Diseases of Laying Chickens

Respiratory Diseases

• Respiratory diseases in chickens can be difficult to diagnose because many of the symptoms are the same in other diseases. There is usually a discharge from the eyes or nose, difficulty breathing, and in some cases rale or respiratory sounds. In all cases laying hens will have reduced egg production.

  Fowl Pox, also known as Avian Diphtheria or Canker, is a very common poultry disease, not just in laying hens, but in all poultry, domestic and wild. Fowl Pox is transmitted by mosquitoes, so efforts to control mosquitoes near the flock is a good preventative measure.

  Newcastle Disease and Aspergillosus are highly contagious among poultry and can be spread to humans. Infectious Bronchitis is a disease specific to chickens and is also highly contagious. Infectious Bronchitis and Newcastle Disease are both airborne diseases and can also be contracted by contact with the infection on feed bags, dirty crates and equipment as well as contact to infected chickens.

  Aspergillosus is caused by a fungus that can be found in infected litter and nest materials. It might also be present in the water and feed. There is no cure for birds infected with Aspergillosis. Avoid using sawdust or litter materials that contain bark. Don't use wood shavings that have been wet.

Marek's Disease

• Marek's Disease is a form of avian cancer. Tumors grow inside the chicken, causing a variety of symptoms depending on what organs are affected. It is an airborne virus that will spread to other chickens. There is no treatment for Marek's Disease. Chickens that have the virus in their blood will carry the virus for life and be a carrier for the disease.

Staphylococcus

• Staphylococcus is a soil borne disease. Chickens can be infected by drinking from pools of rain water after a storm. The staphylococcus organism can be passed in the egg and may show up as egg black rot. Other symptoms include lower egg production, lameness, listlessness, and diarrhea. Treatments with antibiotics are effective. Removing sharp objects from the chicken's environment to prevent injuries and removing ground level objects that collect rain water can help prevent a Staphylococcus outbreak.

Equine Encephalitis

• Contrary to the disease's name, birds are the major source of Equine Encephalitis (EE) virus. The EE virus is transmitted primarily by infected mosquitoes, but can be contracted within the flock by cannibalism of infected chickens. There is no treatment for EE. Remove mosquito breeding areas near the flock and promptly remove dead or sick chickens to prevent the disease.

Egg Drop Syndrome

• Egg Drop Syndrome is a chronic disease that affects laying fowl. Brown layers are especially susceptible to Egg Drop Syndrome. Although it occurs world wide, Egg Drop Syndrome is not reported in U.S. flocks. Symptoms include significantly lower egg production, small, thin-shelled eggs or eggs with no shells. It also causes loss of color in pigmented eggs. There is no treatment for Egg Drop Syndrome. A vaccine can be given to help prevent the disease.