Coccidiosis

Coccidiosis in Chickens

Coccidiosis is a parasitic disease of the intestinal tract of many types of animals, including chickens. It is caused by coccidian protozoa. The disease spreads from one animal to another by contact with infected faeces or ingestion of infected tissue.

Most chick and grower feeds contain a coccidiostat to manage exposure levels and control disease. The coccidiostat doesn’t kill the parasite, just greatly slows down its growth. This means that the young chick can still get infected, but not badly. This allows the chick to build up a natural immunity to the infection.

By the time the chicken reached point of lay, at 18 weeks, they will normally be able to resist infection.

The coccidiostat for chickens should only be fed to young chickens. 

Carefully read all warnings on the bag of feed.
Some coccidiostats are quite dangerous if fed to the wrong sort of animal.

Raising Chicks Without Using a Coccidiostat 

It is possible to raise chicks on feed that has no coccidiostat in it. This is not something I'd recommend trying unless you're fairly experienced in rearing chicks. A person wanting to produce organic eggs might decide to do it.

The parasite thrives in wet conditions, and can be killed by sun and dryness. By keeping the area you are rearing the chicks in scrupulously clean, dry and free from faeces, it's entirely possible to rear healthy chicks.
Red Hen Chick is a good medication-free starting feed.