My EE are about 9 weeks old. They have been out in our Northern Ohio coop for about a week. We have deep litter that they can snuggle into if they get cold, but they have been sleeping on their roosts for about a week now. We have 2 windows (east and south) that are open 24 hrs. They have been doing great! It's been fun to see how they put themselves "to bed" by 8:30 at night, and have been roosting without being taught. These are are first chicks (10 more in the brooder at 3 weeks and 2 days!), so hopefully by the time the young ones are out, the EE will be willing teachers! The night air seems to be fine, unless it gets unseasonably cold.