Basic design is a single 4x8 sheet of plywood as a floor. I believe 3-4 inch plywood. Tongue and grove walls. Windows were old storm windows found in an alley.
Hardwire cloth for the vents. A triangle of the same tongue and groove wood fits over the vent. It is about the same size as the vent hole and can slide to the side or can be removed completely to adjust the size of the vent.
The girls most often roost in the rafter rather than on the roosting bars.
Slide out tray for easy cleaning.
You can see at the back the tray sits on a couple of 1x2s.