I have recently treated my Orpingtons for Coccidiosis. They have been off Corid for aprox. a week now. They are showing symptoms again. Is it okay to re-treat them or will it cause an immunity? I'm assuming that since they have become ill again (or it never really went away to begin with) then I can't cancel out any "immunity" because they obviously don't have any. Is this a correct assumption? Thanks so much!