-31 this morning with a 20-30 mph wind and the water in the chicken coop was not froze. It is in a black plastic pan on the floor. No heat light or heat of any kind, other than chicken heat. I wish my house was built the way I made that coop. I am getting 20-25 eggs a day.

Nice MJM.

With a red lamp over the water pan ...it's open water in mine but only 20° inside

Deep litter?

I’d like to know how you built that coop!

Yes. It sure helps.
The coop has 2x6 walls with 6" of glass faced insulation. Ix12 ship lap, tar paper and then pole barn steel. roof is plywood tar paper and pole barn sheeting over that. Ply wood inside on the walls and ceiling. Nine inches of glass in the ceiling. Two windows and glass door on the south side. 3/4s the south wall is glass. I made the door. There is a stub wall 16" tall under the door.

Do you have any bowing issues with the shiplap that wide?

No bowing. I used ship lap because a guy was taring down a lumber yard and was selling the wood. I stopped and he said any ship lap I pulled I could have. I pulled two PU loads of it after work in a few evenings. It was real flat to start and I am sure I nailed it more than most would. The walls are only six foot high. Roost is hinged to the wall just down from the ceiling and can be lifted up to clean. I just wire it up to hold it out of the way.

I use a heated water bucket with nipples , it turns itself on and off when it gets below freezing so it dont waste much power.

A coop insulated too well will frost up bad after a while and condensation can be a problem.

My door frost up. I have a 6" stove pipe that run out on a gable end and down inside the coop. It really helps. It was longer and went down with in a couple feet of the floor, but I shortened it up some. I built the coop over 20 years ago. So I think it works.