Some common diseases in chickens include:

• Marek’s Disease: A viral disease that affects the nervous system, causing tumors and paralysis. There is no cure, but a vaccine can prevent it.
• Avian Influenza: A viral disease that affects the respiratory and digestive systems, causing high mortality rates. Antiviral medications may be used to treat it.
• Fowl Pox: A viral disease that causes skin lesions and can lead to respiratory problems. A vaccine is available, and affected birds can be treated with antibiotics.
• Coccidiosis: A parasitic disease that affects the digestive system, causing diarrhea. Antiparasitic drugs can be used to treat it.
• Newcastle Disease: A viral disease that affects the respiratory and nervous systems, causing high mortality rates. Antiviral medications may be used to treat it.

It is important to consult a veterinarian for proper diagnosis and treatment of any disease in chickens. Preventative measures, such as proper sanitation and biosecurity practices, can help reduce the risk of disease outbreaks.