In the interest of better safe than sorry, I decided to make my own chick grit from the regular grit I had on hand.
I took a bit of the granite grit I had, wrapped it in a couple of layers of parchment paper and then wrapped that in duct tape. I then took a 5lb hammer to it on the concrete...
I've got chicks in a run with their mom and they're eating all kinds of stuff. I think they need grit. They're 9 days old, btw.
I wasn't able to find chick grit at either of the places we buy our feed and regular grit, so I got bird gravel at PetSmart. They only had the 8-in1 kind with charcoal...