Chickens are one of the most commonly kept domestic animals, for both meat and eggs. They are most prone to parasites including mites and worms. Chickens need a clean living environment with fresh water always available. If a chicken dies, remove the carcass as soon as possible as a majority of diseases and infections can still be contagious to other chickens.
Avian Influenza, commonly known as bird flu, is a strain of 'flu that has adapted and can infect all types of bird. The most common symptoms include respiratory distress, diarrhea, white spots on the chickens legs and a discharge from the nose which may have blood spots in it. The influenza is spread through the manure of the birds as well as the improper disposal of the birds carcasses.
There is no known cure for avian flu but antibiotics will treat mild forms of the virus. A vaccination will control mild forms of the flu. The only way to control more lethal forms is to destroy all infected animals as quickly as possible.
This disease, caused by the bacterial organism pasteurella multocida, produces high temperature and green diarrhea in chickens. The wattle, the fleshy growth hanging from the chicken's neck, becomes very swollen. The chicken's joints may also become swollen.
If left untreated this disease can very quickly kill the chickens. Drugs available to treat fowl cholera include penicillin, erythromycin and tetracycline. After the course of medication the disease often recurs and may require long term medication. The bacteria is easily destroyed using disinfectants but it can persist in soil for prolonged periods.
Cecal worm is the most common parasitic worm found in North America and attacks the chicken's cecal, a section of the large bowel. The worms measure ½ inch long and are white. Chickens who have these worms may be dehydrated and pale and will have a lower egg production rate than normal. It can be treated with levamisole which is effective against many parasites.
Botulism in chickens is caused by a bacterial byproduct and by drinking infected water. Symptoms may include tremors which quickly progress to paralysis of the body. Chickens usually die within a few hours. Antitoxin is available to treat chickens but is very expensive. There is currently no vaccine available to treat botulism, as of 2010.