Because of the awful heat in our area (So. California), I’ve been running misters a few hours a day to help keep the chickens cool. Unfortunately, I’ve just noticed that there is a layer of stinky charcoal looking sludge about 6” below the sand surface. My question is whether this is safe for my chickens. They are digging holes and scratching around in the wet sand, and they love to snack on the sand particles. So I’m just concerned whether it’s dangerous for them to ingest this stuff. Any thoughts?