Is your roof hinged?
I see a latch there. the roost bar is even with the bottom edge of the green roof, right?
what I would consider doing it it’s not much trouble, is lower the roost bar a foot or even up to 2’ if you can, and then add ventilation under the roof, meaning if it is hinged, open it 8” or so and make that the new “closed” position (it will be less steep now) and Frame out/ screen off that opening. Now your hens will be mostly below the level of the ventilation. Here is mine, my roost bar itself is probably about 4” below, and 2 feet away from, the big front window that extends the length of the roof. My climate is a little warmer.
being up high in the coop as you have it would be bad if you don’t have enough ventilation (like closing windows), that is a recipe for frost bite as their warm breath condenses and freezes all around them. Give them head room, and ventilation, And you’ll be doing awesome!
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