Now that I've looked at pic closer by lightening,
I can see you maybe have tubs in there(?) so don't need a front lip.
Also can see that curtains are really unnecessary, it looks cozy in there.
The thought of thumbtacks coming loose in coop makes my shudder with horror,
they could eat them or...
I'd a add landing bar(perch) and front lips 3-4" high....forget the curtains they don't need them, those nests are cozy enough. How wide and tall are the nests?