My coop is dry and my run is 1/2 roofed and I tarped the other half now, but apparently where we built the ground stays wet after rain and we have had a lot. the chickens have free range of about 1/4 acre and are out of the run but I just hate the damp sometimes muddy run. I read this "Coarse Shellgrit - Ideal for the more exposed coop that may get wet inside. Deep level will ensure that water is not in direct contact with the feet. No or low dust levels. Needs to be raked in the winter months to keep from smelling." I can not find where to buy this in bulk enough for a run not a coop. Help!