Diseases and parasites of turkeys are discussed in detail in Farmers' Bulletin 1652, Diseases and Parasites of Poultry. Coccidiosis often causes heavy losses in young turkeys. It is best combated by carefully cleaning the brooder house and changing the litter once a week during the brooding period, keeping the litter dry, and using wire-covered feeding platforms. Turkeys are subject also to the attacks of various species of worms, but treatment for worms should not be undertaken until the presence of worms has been determined by examining the droppings or by post-mortem examination. BLACKHEAD Although other infectious diseases sometimes affect turkeys, blackhead is by far the most destructive ailment. It is caused by one of the Protozoa and is primarily a disease of the caeca (the blind pouches of the intestines) and the liver, but the fact that the head of the affected bird often becomes discolored has given the disease its common name, blackhead. It attacks turkeys most frequently, but chicks are often affected by it without showing symptoms; thus the chickens carry and spread the infection to turkeys when allowed to range with them. A combination of spotted liver and ulcerated caeca indicates that the birds have blackhead infection. Although blackhead affects adult turkeys, it occurs principally among poults between the ages of 6 weeks and 6 months. It is found to a greater or lesser extent throughout the United States. The turkeys affected by blackhead, like all birds having infectious diseases, should be removed immediately from the flock to prevent the spread of the disease. The best procedure is to kill the sick birds and burn or bury the bodies, as no treatment has been found satisfactory. Move the flock to clean ground, if possible; but if this cannot be done, clean out and disinfect the roosting place, plow the ground in the yards, and install a system of yard sanitation. Keep chickens and all other poultry away from turkey yards at all times in order to prevent infection from this source. The organisms which cause the disease may be carried by flies, blown with dust, conveyed in contaminated soil on the feet of the caretaker, or spread for considerable distances in other ways.