Hello, I was wondering if anyone can help me with some questions about treating cocci. I have my normal flock of laying hens, and I bought some meat birds about a month ago. I just recently placed them outside in the coop with my bigger chickens about a week ago. Yesterday I went outside to some meat birds with weird looking eyes, drooping heads, some were by themselves just standing all puffed up and not moving much, etc. I'm pretty sure that this is cocci. Since last night 2 of my meat birds have died, and I don't think a few of the others have long left. Anyhow when I moved them outside I switched to an all flock feed as I was having issues keeping my older chickens out of the medicated feed. My main questions are: Can I treat with Corid? If so, should I treat all the chickens with corid, or just trap the meat birds and treat only them? If I treat with Corid, is there an egg withdrawal period? Is there anything that I can do for the chickens that seem to be pretty far along with Corid? I've been researching a lot, and I can't seem to find some answers. If my older chickens have cocci, it is okay because they have built up a resistance to it. Is this correct? Or do they need to be treated. They haven't shown any signs, but I'm nervous that they will catch something from my sick chicks.