You're still hot
I hope you post pics as you go or when you're done. I'm always looking for improvements

I never thought about having chicks again or dealing with a broody. Fortunately we did so little at first that adding or changing stuff isn't too complicated.
I will suggest that you have the option to cover the other walls with panels if you don't build with 3 solid walls and one open. We do get down to freezing, can get some stiff breezes even when it's chilly and during monsoons you don't want your birds getting soaked on the roost all night. Also, a solid wall helps block some of the heat that radiates from the block walls that surround our yards.
Good luck and share pics!