Well...I think most would say they won't need grit right away, that their starter feed is easy to digest. Right or wrong, I did give mine a little at about a week old...just sprinkled some on their feed like salting your own food. I did that because I began giving an occasional treat (worm or grub). I've also offered a shallow pan of sand for them to dust "bathe" in (w/ a tiny bit of DE mixed in). I've seen them eat a little of that too, so maybe that kind of acts like fine grit too???