I have 8, five week old chicks. I just finished building my coop and run. The chicks were outside all day with free range of the coop or run and it was 60-70 degrees with on and off raining. They were all fine. Even in the 60 degree weather they weren't huddled together in the coop. I'm wondering when I can move them in there full time. I'm including a picture of my coop because it's a little different than other coops. It's made out of pallets and plywood, but the pallets aren't filled in (they have chicken wire on them though). This provides a lot of ventilation. In the winter, we will fill in the pallets with plywood that has insulation on one side of it. I can't really change the coop at all. The only thing I can do is wait longer to move them in. I think they would be fine (with the heat lamp in there too) but I want to get expert opinions.