They feel safer in a sheltered place all huddled together.
Just keep putting them on the roost...best to do this well after dark so they can't see to jump back down.
Do they get up on the roosts during the day at all?
If not, put them up there during the day too, just to get them familiar with it.
How long have they been in this coop?
Looks like a huge coop, nice!
Have any wider shots of it inside and out?
Can't quite place where the huddle spot and the feeder is in the roost pic.