a few years ago I was losing chickens one right after another. I sent a dead bird in to be tested and he had cocci. I treated the birds and cleaned the run and coop. But it seems every season when I add new birds I always end up losing one or two. Should I treat them with meds before adding them to the coop? I always do a through cleaning before adding new ones. I just don't want to keep losing birds that I've grown to love. Help!