I went to the building materials section of my local home improvement warehouse and bought a big flat bucket the masons use for mixing cement. It is roughly 24 wide by 18 wide by 6 inches deep. It has a flat bottom and a rolled edge lip. I recessed it into the floor of my run and fill it with play sand. They lay in it, they poop in it and apparently they eat it for grit too. Dual purpose dust bath.
