Diseases in chickens pose significant challenges to chicken owners and poultry farms worldwide. From viral and bacterial infections to parasitic infestations and fungal diseases, chickens are susceptible to a wide range of health conditions that can cause morbidity, mortality, and decreased productivity.
This article is to introduce some of the more common diseases and illnesses that may appear within your flock.
-Note-
Please keep in mind that I am not a vet and the below is meant to be an overview of common diseases based on my own research and having spoken with avian vets over the years.
This information is not meant to be a diagnostic tool for determining your chickens’ health issues but instead a general list of diseases that chickens may contract for educational purposes.
If you have a chicken that you believe is sick, please contact your local avian vet since they’re the best option for giving you a diagnosis and possible cures.
- Aspergillosis: Aspergillosis is a fungal respiratory infection caused by Aspergillus spp. It commonly affects young chickens and is associated with damp, moldy environments. Symptoms include respiratory distress, lethargy, and decreased appetite.
- Avian Influenza (Bird Flu): Avian influenza is a highly contagious viral disease that affects birds, including chickens. It can cause a range of symptoms, including respiratory distress, decreased egg production, and has high mortality rates in severe cases.
- Blackhead Disease (Histomoniasis): Blackhead disease is a parasitic infection caused by the protozoan parasite Histomonas meleagridis. It primarily affects turkeys but can also impact chickens, causing symptoms such as liver damage, diarrhea, and has high mortality rates.
- Bronchitis: Infectious bronchitis is a highly contagious viral respiratory disease that affects chickens of all ages. It can cause respiratory distress, nasal discharge, decreased egg production, and poor egg quality.
- Bursal Disease (Gumboro): Infectious bursal disease is a viral infection that primarily affects young chickens, causing damage to the bursa of Fabricius (specialized lymphoid organ in birds) and immunosuppression. It can result in increased susceptibility to other diseases and decreased vaccine efficacy.
- Cholera: Fowl cholera is a bacterial infection caused by Pasteurella multocida. It can affect multiple organ systems in chickens, causing symptoms such as sudden death, swollen wattles, respiratory distress, and greenish diarrhea.
- Coccidiosis: Coccidiosis is a parasitic disease caused by protozoa of the genus Eimeria. It affects the intestinal tract of chickens, leading to diarrhea, weight loss, decreased egg production, and sometimes death, especially in young birds.
- Coryza: Infectious coryza is a bacterial respiratory disease caused by Avibacterium paragallinarum. It can cause symptoms such as facial swelling, nasal discharge, difficulty breathing, and decreased egg production.
- Egg Drop Syndrome (EDS): Egg Drop Syndrome is a viral disease caused by the adenovirus. It primarily affects egg production in laying hens, causing a sudden drop in egg production, soft-shelled eggs, and poor egg quality.
- Erysipelas: Erysipelas is a bacterial infection caused by Erysipelothrix rhusiopathiae. It primarily affects turkeys but can also impact chickens, causing symptoms such as fever, skin lesions, arthritis, and sudden death.
- Fatty Liver Hemorrhagic Syndrome (FLHA): A metabolic disorder characterized by the accumulation of fat in the liver and sudden hemorrhage. It primarily affects laying hens and is associated with obesity, high-energy diets, and insufficient exercise.
- Fowl Pox (Avian Pox): Fowl pox is a viral disease caused by the poxvirus. It affects the skin and mucous membranes of chickens, causing wart-like lesions, scabs, respiratory symptoms, and decreased egg production.
- Gapeworm: A Gapeworm infection is caused by the parasite nematode Syngamus. It affects the respiratory system of chickens. Infected birds may exhibit symptoms such as gasping, stretching the neck, and respiratory distress.
- Infectious Laryngotracheitis (ILT): Infectious laryngotracheitis is a highly contagious viral respiratory disease caused by the herpesvirus. It affects the upper respiratory tract of chickens, causing symptoms such as coughing, gasping, and severe respiratory distress.
- Marek’s Disease: Marek’s disease is a viral infection caused by the herpesvirus. It primarily affects young chickens, causing tumors, paralysis, and immunosuppression. Marek’s disease is often fatal and can spread rapidly within a flock. For more information on Marek’s Disease click HERE.
- Mycoplasma Gallisepticum (MG): Mycoplasma gallisepticum is a bacterial infection that affects the respiratory system of chickens. It can cause symptoms such as sneezing, nasal discharge, swollen sinuses, and decreased egg production.
- Necrotic Enteritis: Necrotic enteritis is a bacterial infection caused by Clostridium perfringens. It affects the intestinal tract of chickens, causing necrosis of the intestinal lining, diarrhea, decreased growth rates, and occasionally sudden death.
- Newcastle Disease: Newcastle disease is a viral infection that affects chickens, causing respiratory, nervous, and digestive symptoms. It is highly contagious and can lead to high mortality rates in unvaccinated flocks.
- Salmonellosis: Salmonellosis is a bacterial infection caused by various strains of Salmonella bacteria. It can affect chickens of all ages, causing symptoms such as diarrhea, lethargy, decreased egg production, and sometimes death.
