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.