The slightly larger grain sand is great in somewhat sloped runs (isn't lost through erosion or completely worked into mud when it rains for awhile - stands up to the turkeys best efforts). We just keep dumping and raking in `play sand' (fairly coarse compared to `tube' sand) on the high side of the runs every few weeks. Also works great as a base for coop flooring on wood, mix in some DE and toss on the pine chips and straw.