It is impossible to disinfect a coop. Coccidia are in the soil and in the droppings of most chickens to some extent. As they grow, they will usually build up a tolerance to cocci in the soil anywhere from 11-20 weeks of age, unless there is a problem with immunity or a new strain is introduced from other soil. Usually, stirring the bedding often to keep it dry, changing it when it gets really dirty, and then adding new bedding can help. A vet can do a fecal test on several fresh droppings collected, to look for coccidia or worms. Corid (amprollium) used in the water for 7 days is a common treatment for an outbreak. Other medicines used are sulfa antibiotics and toltrazuril, especially in other countries. Symptoms to look for are sleepiness, standing hunched or puffed up, poor appetite, ruffled feathers, or diarrhea with mucus or sometimes blood.
