Does anybody use plant flats for poop trays? You know, the kind - without dividers - that annuals come in, or you can buy them to start seedlings. Seems like it would work, doesn't it? Easy to remove and hose down - cheap enough (free?) to replace when they start to break. Hmm, it would be a problem if the hen jumps on the edge and flips it, though. Any thoughts or solutions?