I was at Agway ordering chicks and saw this gravel. It was only about a dollar so I got it, thinking I could use it for grit for my chicks once they started getting treats. But later, I looked at the back and it says it contains oyster shell and charcoal: I know that oyster shell is not good for baby chicks, because it weakens their bones or whatever, and it seems to contain a lot: So now I'm thinking it would work as their calcium supplement when they grow up, with a bit of added grit in there. My question is, will they be fine with the charcoal? The box says it "combats hyperacidity and sweetens the stomach," but this was made for Parakeets, Cockatiels, and Parrots. There doesn't seem to be a lot of charcoal in the mix, but I know it makes dogs throw up. I could separate it by putting it in water and letting the charcoal float and the rest sink, but... more work... and if charcoal is beneficial, that would be nice. So, is charcoal fine for chickens in small amounts?