We tilled up our chicken pen and then added sand to it, I love it we are going to get a couple of more tons of sand in the next few weeks I love the sand the dirt here is mostly clay and it does not drain worth anything so the sand helps it keeps the smell down and it also no standing water now. we used the dirt we tilled in my raised garden bed I have plants popping up all over the place. Its great I love the sand it makes cleaning easier, I am not sure about using the sand in the coop yet been using straw I might go to sand in the coop when we get it built not sure. but I do love the sand in the pen don't have to buy gravel anymore and the chickens love it also. So if you have the chance go with sand makes cleaning much easier and I am hoping that this summer it will help with smell.