The chicken tractor I bought has a screen floor which allows the poop to fall through to the run below. The previous owner said they kept it like this because it was easy to keep clean and the birds stayed on the roost anyway. However, it seems to me that it would be hard on the chickens feet and not the most comfortable. Should I leave it like this or put some form of bedding down over the screen? If I do put bedding down over the screen, how often do I have to replace it? I am not sure I have the space or layout to put a droppings board.Thanks!