The breeze has to be strong enough to ruffle the chickens feathers, to really effect their warmth. That's a strong breeze hitting them. If you ever played hangman as a kid, make something similar and put it on your roost bar. Hang a piece of tissue, mimicking the height of a roosting chicken and...
X 2 ^^^^^
You could also use wide ribbon to hang. I'm betting that the breeze is not even hitting the roosting area very much to have any effect on your ladies.
I used a piece of cardboard zip tied to the door opening, on an earlier brooder, but you need to have a way to get in. I had access through the cover I made, on the dog X pen along the back wall.
In my post #184, I attached 1/4 inch netting to the cardboard, then attached everything to the door...
Yes, if you made it to heavy that could happen. Try to keep everything open as much as possible. If you have a small fan you could put inside to keep the air moving, it may help to cure it faster, since it been a couple weeks already. I would press down on the cracks if they are damp and see if...
Nest boxes inside to the left of the board and raised up will work well. Don't forget to have a landing board in front of them. I have mine inside the coop, raised up. I don't have to stand in the rain to collect eggs and I get to check things out inside.