I went to your byc page to look, and it was blank.
I don't know how warm it is where you are, is it cool or breezy by the roost?
When I first finished the big hen coop, my birds would roost on the back of the brooder they had grown up in, near the back wall of the run. I screened that area off with window screen but was terrified that a raccoon would find a way to grab one. I moved them to the perch in the coop at night, but they wouldn't roost there.
Finally I took the brooder apart, and for about a week they did roost in the coop. Til I built the 4 tier run roost. It's safer, further from the wall than the old brooder, airy in the hot weather, under a roof so they don't get wet, and unless it is near freezing, that's where 4 out of 5 hens sleep. For some reason the Barred rock moved into the coop about 2 or 3 weeks ago, but she is on a roost.
I like the idea of multiple roosts. I actually have 3, but no one has used the east roost in a year now.
Could you change your nest boxes in some way - go to pet carriers with a ceramic egg, or something like that, for a week or so, and maybe add a couple of more perches?
Gypsi