Also when it gets real hot in the summer we give them a shallow pan, upside down trashcan lid, smallest size kiddie pool, something that'll hold a couple/three inches of water for them to wade in. Not so deep it's up to their bellies or they feel like they have to swim though.
They'll stand in there now and then to help cool through their feet as the blood vessels run right under the skin with no feathers insulating.
Might only be applicable there in the very hottest month or something. Down here we worry about keeping them cool as much or more than keeping them warm.
If you see them panting like a dog a lot and getting lethargic in the heat, try that.
I put our coop and run area in a spot that's shaded most of the day and especially in the afternoon and still give them a wading pool but you not gonna have some condition where it's 100 degrees for weeks.