I've got 3wo chicks who were brooded and hatched by a Mama Hen. They've been continuously living in the coop & run with their Mama and then with the big girls when Mama lead them out of the nesting box.
I worried about how I'd get them chick feed and chick gauge grit but they've been foraging for themselves in the dirt floor of the run for a couple weeks now. The only things I'm supplying are whatever greens are left over after the hens get bored with them and an occasional handful of all-flock feed thrown on the ground. I take it they get whatever is naturally in the dirt to help grind whatever it is they're actually eating.
God! I sound like a HORRIBLE Chicken Mom but they've been growing and thriving with only attention to their ground level waterers. And, in my defense, I did try to supply them a small feeder with chick feed & grit but, hey!, it was new and the big girls were all over it and it was history within about 5 minutes...
When I brooded chicks inside in a wire kennel I gave them chick feed with some chick grit sprinkled on top.
All things considered, having a Mama Hen is TOTALLY the shitz!!! I don't even have any Mean Girl issues.