My duck pen is Messy Messy Messy! I was using hay in the pen but it gets messy within a few days. How good does sand work in duck pens? if I use the white play sand type wouldnt it keep the water cleaner? theres muck under the hay and they love to mix that with their water... I also figured Sand would wash clean when it rains and dry alot easier then muck and hay. So who all uses that for duck pens?