It was down to 24 at nite a few days ago here. WE dont' put any heat on ours, just make sure they a can get out of the wind. Never lost one to cold. We keep our chicks in brooder boxes with light and on our Juvies we make sure they are draft free and have hay to snuggle in. The wind is aweful today. Blowing around 20 miles an hour. Very cutting.