Hi, I'm new with this and am building a coop inside my barn. The chickens will exit the coop and be under the barn overhang (formerly used to shelter equipment) then they will be able to go onto a grass run. The overhang section they first go onto (about 8x8') has deep driveway gravel. Do I need to remove this gravel? Will it damage their feet? Thanks so much to anyone who will answer my silly questions.