I think it depends on the bird. As long as their wings are not clipped, they should be fine. When I was a kid, I had a pet bantam rooster. We both got a lot of exercise. I would carry him up to my second story bedroom, and let him fly out the window. When he landed, he'd crow up a storm, like he was real proud of his accomplishment. Then I'd run down, grab him and run back upstairs for a repeat performance. I don't think I'd do the same thing with a full sized laying hen, but if the hen gets up, she should be able to get down. A lot of hens will roost in trees if given the chance.