I have a small (extended) prefab with two laying nests. Normally used by all hens to lay their eggs. Now 5 hens but also sufficient for 8 bantam hens (not every day layers). It has no curtains.
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The lid is oriented south, and it got very hot in there. A car sun screen does wonders.
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Inside. Last year when I had two black broodies.
During the first days, the hens made sure, the chicks stayed in this part of the coop. For the chicks I made a wide plank/board (with fabric) that was less steep than the stairs. The chicks could easily go up and down.
I have another seperate nest box (pic from the shop) and I used a simple cardboard wine box for laying nest when these two broodies occupied the regular nestboxes. But I had to seperate the broodies from the flock anyway because they were disturbed too much. They preferred the cardboard box under the roosts and poop board.
The other seperate nest box is just a few inches above the ground and a better accommodation for broodies. It was used for two broodies about 3 years ago. It was less safe but the other hens could go on with their usual routine withouth bothering the broodies.