I’m guessing you cannot get to them on the rafters after they are asleep and take them to the coop? They are generally pretty easy to just pick up off the roost after its dark. You certainly don’t need to hurt yourself trying this and in many barns those rafters are pretty inaccessible. This would never work in Dad’s hay barn unless the hay was stacked right up there.
My suggestion is to food train them. Give them treats a couple of times a day, using the same bucket or container and rattling the food in it. Use a special call, maybe “here chicky chick” when you do this. It will take patience but they should start coming to you when they hear the call or you shake that bucket. Trap them inside the coop and leave their butts locked in there for a few days, at least a week. That may or may not work. Sometimes it breaks them of the habit of sleeping on the rafters and gets them used to sleeping in the coop. Sometimes not.
Another option is to do all this and lure them into the coop a little before bedtime, then lock them in there overnight. You’ll have to be consistent every night. It might make it easier to trap them if you build a run, temporary or permanent, around the coop. That gives them more room too if you leave them locked in there.
Good luck. That can be a hard habit to break. The older ones may eventually teach the younger ones to sleep in the rafters too. That’s another reason to break them.
