Hi -- I'm new to chickens and composting. I have 3 hens in a 4x12 foot run with about 2 inches of sand. The ground is hard clay and there's weed barrier (plastic I think, but porous) under that. The garden is raised bed with compost that I bought a few years ago. I just bought a compost tumbler to start making use of the amazing amount of poop 3 chooks produce. I put in my first load of cardboard and manure today. When I was moving around sand in the chicken run, I found a layer of clumpy sand that smells horrible. I'm guessing it's urine, but really am not sure. It was pretty widespread, not concentrated in the usual poop spots. My guess is that it's chicken urine that somehow binds the sand together -- it looks like cement, and chunks hold together when lifted, but the material will crumble easily. Can I toss this stuff in the composter? Thanks for any advice!