I always provide store-bought grit for my chicks/chickens, even though they free-range. I give them Parakeet grit when they're less than 2 months old (it's only like $2 a box, and they love it like a treat). I use Chicken Grit (ground granite, like tiny rocks) sprinkled on the ground near the coop for the older birds. I know people say they can find their own grit on the ground outside, but I'm not sure about that here. Our "dirt" is black clay...when it rains, it's very slippery. I don't see any rocks or sand in our dirt. If I lived near my Dad where there is a lot of natural rocks and sand then I probably wouldn't buy grit.