This is a public service announcement since there seems to be a misconception surrounding coccidiosis. If you have a typically healthy flock that is in contact with the ground and they mysteriously develop diarrhea all over their back ends, gather some poop and take it to the vet for analysis (usually only between $5 and $20 for the test). In the majority of local cases (here in SWVA), the major problem with "poopy butt" aka diarrhea in older birds is coccidiosis. Not worms, not vent gleet, COCCI. Coccidiosis does not just occur in chicks; it is extremely common in older birds as well. Don't just assume that it is worms or cocci before getting the poop analyzed by a vet. Let me be clear: most soils have some coccidian protozoa in them. Theoretically, you can gradually build immunity in chicks by adding small amounts of litter from the adult coop to the brooder. When birds become overloaded with the amount of protozoa living inside of them, they have diarrhea and, when the protozoa have begun to damage parts of the digestive tract, bloody diarrhea. Eventually, coccidiosis can cause severe prolapse and/or death. In older birds, death is not as common, but it most certainly does happen. Obviously, immediate treatment involves a cocciostat. There is a theory that says a good immune system, coupled with probiotics, can keep cocci manageable in an adult flock.