Can someone tell me if there is a certain grit for chickens only or is it the same grit you would give to birds? I have some that said for birds on it but my hens don't seem to care for it. I notice it smells odd and pretty nasty?? I understand they need grit if they are given leftovers or anything other than chicken food?? They only get to free range a couple times week when I'm able to be there to watch them as they're still only about 12-13 weeks old and I'm scared a cat or a hawk or anything really could get ahold of them. They do walk around in our lanai every morning but I realize that's NOT grass and they're not getting their grit in there.