I have two Orpington chicks that are 4 weeks old. They were hatched in the coop and the mother did a great job keeping them warm for a week or so, but they would stay under her. Then we put up a heat lamp in the coop attached to the ceiling and we used a chick warming pad under where they were laying. This worked out very well and they have been very active. I had to construct a small 15 inch wire fence to keep them from going near the opening the other chickens use to enter the coop at the other end. This also worked very well until just a few days ago. Now when I go out to check them in the morning, they are on the other side of the fence. I don't know how they do it, but they do it every night. I move them back and they stay there all day while the small door is open. So, it is a wide range of temperatures here in the mid Atlantic. I want to start letting them outside into their run, but at what temperature should I do that? They have feathers but are not completely feathered out yet. Because they have been in the coop since day one, the rest of the flock has completely accepted them and there are no worries there. Also, our coop is raised about 30 inches and the birds use a ramp to get into the coop. Any suggestions? Thanks for your help.