Personal because of my chickens not roosting but wanting to be as high as possible, I would make them a nice huddling area up off the ground. See if they like that. From what I've read, it's best if they are up off the ground. I should probably include, mine have huddled from the very beginning...
That is how all of mine sleep also. All 5 have never wanted to roost. They just sleep all huddled together about 4-5 feet off the ground. I clean the poop out every day.