I screwed the front door on and added a 2x4 inside to roost on and then threw in some hay over the wire floor. I figured the chickens were not used to walking on wire and the hay would be less of a change for them at first. Tonight will be 8F. with 20-30 mile an hour winds. I figured the hay would help keep lessen any draft so I also added some to cover the opening at the bottom between the tractor and ground.
The front door is covered in plexiglass that I got from an old storm door, and a small piece from another project. An area about 8x10 inches is left open in the upper left corner for ventilation.
Here is a view looking in from the front. The chickens are used to roosting higher so having a roost that is only 2 inches high, for now, will be an adjustment.
Update: I just went out with a flashlight to check on the chickens. They are in the front right corner and one is in the nest box. I guess they don't consider a roost that's 2 inches high a 'real' roost, or they are smart because I think they picked the most sheltered area in which to bed down.