I have a sick EE rooster that is almost 6 months old. The only recent changes are that I switched the feed to Layer feed. It has been really cold here below zero every night. My coop is well insulated but am having issues with alot of moisture. He has some black spotting on his comb and he just just stands with a drooping head. He has had normal poop other than it being green and white, it is usually black and white. I looked for mites but didn't see anything. I read on another thread that you could give a sick rooster some Sulfadimethoxine so I bought some but not sure what to give him as a single dose. Do I just use a dropper and pry open his beak to give? I did give him a couple of drinks of honey water and he drank that, but is not interested in food. His eyes are clear and he doesn't sound like he is having any issues with breathing. Any help would be appreicated. Also does anyone know at what age you should start de-worming?