I have three types of chickens: American Dominque, American Game, and Missouri Dominque (something I am developing from crosses of the first two). The dominiques have no trouble with cocci regardless of how they are kept while some the American Games (as a function of line) get hammered by cocci when ground is wet for extended periods. Simply treating water with coccidiostats and medicated feed is not effective with free-range birds in my setting. So, when sustained heavy rains hit I police up broods and hens and place them in rabbit hutches. They are then fed and watered with coccidiostats where they are not exposed to the wet soil nor as much of their own infected feces. They also can ingest only the feed and water I provide ensuring they get the proper dosage. Broods are confined for a week as outbreak runs it coarse with much fewer losses than realized with birds allowed to stay on ground. After the week of treatment they can be released and the cocci will no longer be a threat regardless of ground conditions because the chick immune systems have gotten a handle on the protozoan. Keeping broods up off ground from hatch does not work because chicks do not get the exposure required to develop immunity later.