Fine, change the word resistance to tolerance in the explanation, and the rest still holds true. I don't claim to be a genius, and I don't generally parse specific words when the general meaning is clear. The explanation I gave was to simply to clear the confusion regarding why the chickens could still possibly develop coccidiosis even if previously exposed. I personally, having experienced coccidia outbreaks, would never consider any bird I own "immune" to coccidia. If the OP can get a fecal done, that would be optimal, however many people who post here to do not have a veterinarian option.