So I had an initial respiratory illness in one of the younger chicks...I treated everyone since they free range together (I have several cooped by age groups). Then right after treatment (I fed Aureomycin crumbles), I had some of my 6 month old birds get lethargic, runny stool, and I found one bloody (I had started Corid in the water at this time) & a couple of days ago I noticed the only bantam I have with a swollen eye, like down in the corner. Figured it was just irritated from being poked, but today I noticed it being lethargic & gasping. When I inspected it's mouth, it;s little trachea was making a slight "pop" noise every breath. Started feeding crumbles figuring it was purely respiratory. Then saw someone online recommended Oxytetracycline for something similar....so I started that ib the water, Got a little into it;s mouth, but didn't want to choke it so I couldn't force it. It had some watermelon not long ago. Seems to be slightly perkier, but I just checked on it and saw bloody stool. I just ran Corid through everyone's water for a little more than 7 days and everyone has seemed ok during the past week up until this. Why would it still have cocci? Is this cocci or some bad resp illness? Does it sound like something this chick will be a carrier of? Any knowledge is appreciated. I will be breeding & selling eggs, so I don't want to be selling sick birds.