Okay did putting them into a different coop cause any change? Did you build the coop yourself or was it one of the kits made with osb? It could have something to do with the building materials. I'm just looking for anything here that could cause an eye irritation and show the symptoms you have talked about. Where you never mention any paralysis in these birds or any trouble walking, I am hoping it's something else besides the Marek's that you thought it might be. Has the antibiotic shown any improvement in them? I know you just started but sometimes you can see something to make you think it is working.They were previously in an outdoor mini coop with a run. Inside the coop there was hay bedding, I changed it weekly sometimes twice weekly and it did get pretty gross sometimes before I could get in there and clean it good. They are now in a full size (huge) coop and it is much easier to keep clean because of the size.