if you use chick starter and they go in the coop at 4-5 weeks with access to 'dirt' and sand you wont need any .. one 'large' bag of chick starter will raise 4 chicks to almost grown lol .. couple months anyway .. of course you can supplement if you want with all kinds of expensive stuff if theyre your babies and pets like anything else and they probably will look healthier lol .. we're talking about chickens here .. they do good with little help generally ..
Chicks dont need grit until you start feeding them something other than starter grower at 10/12 weeks. Treats like scratch, fresh veggies and herbs, sweet potatos, scrambled eggs. Good nutritious treats with lots of vitamins.
I stopped using chick grit years ago. Heck, I don’t use grit for my older caged show birds. Never any issues. The parrot folks stopped using grit a while ago, and there’s debate on if we should even be giving it to birds.