I will be using sand over concrete on my 4x8 chicken enclosure. A nice thick layer. I plan to attach a run to the structure in the near future to get them out. I've read that about once a year the sand should be replaced with new clean sand. My question is, how do you dispose of the old. I'm on 1/2 acre of land, rural area. So I'm wondering how or where to dispose of the old sand.