Under the roosts... I was thinking of a removable plywood sheet, with chicken wire over it so the birds don't sit on it and a wooden wall around so litter doesn't fall in. The board could be pulled out from the outside. There would be a floor underneath this tray, and a low, long horizontal "door" on the outside would be able to be flipped down so the tray can be accessed. It sounds confusing, but really is simple--in theory, anyway. How does anyone else do it?