landing

I'm putting the finishing touches on my coop, and now that it's much less abstract, I'm starting to look at the roost and be a little concerned. Everything I read online about the roost talks about how high it should be, how far from the wall, how far from the roof, how much space per chicken...

These are my boxes. They are about 18-24" about the floor. The girls dont like them :( I have heavy breeds (buff orpington) and they will be getting curtains this weekend. Should they have a landing bar like the one shown in the drawing below? Thanks!

In my coop I have perches at roughly 3', 4', and 5 1/2' (had one at over 8' but it's been removed). While the girls don't hesitate to jump from the 4' perch to the floor suddly a couple don't want to jump from the 5 1/2' perch to the floor. And they refuse to use the intermediate perches as a...