Oh mine haven't had a lamp really since I got them except when we went out of town for a couple days I wanted to make sure the water wouldn't freeze so I put a small bulb in it for that. Otherwise they're fine heat wise. They are definitely fully feathered. I wasn't sure at first but yeah, they're fine. The problem is the rain, snow, etc (wet chicks plus cold) and the grannies. The grannies have not showen them much attention so far except to be apparently afraid of them. This is also part of the reason I got 5...if one of the adults decides to go nuts and go after a chick, they are like a school of fish and scatter, kinda confusing the adult who might not be able to just pick one to chase...kwim? Anyway, I was going to stick them in the coop for the night with the grannies and the fix the door so only they could get out in the morning and the grannies would be stuck inside but if they are all wet, I will probably bring them in and put a light on them for a bit to make sure they get dried off and don't get chilled. I don't trust wet + cold just yet and it's prettty chilly.