I'm new at this too, but from everything I have read and people have been kind enough to share w/ me, their main food should be medicated chick start, and if this is ALL they eat they do not need grit. If they eat anything else w/ it they will need small grit. I have 23, 2wk old EE's in a sandy brooder (sand takes care of their grit needs) They get medicated chick start w/ plenty of "treats". Feeding them treats is such a hoot!!!!!
So far the treats have been chopped apples (no seeds), yogourt, crumbled cornbread, insects caught in the yard, scrambled eggs, and oatmeal, chopped pears, chopped salad veggies (we really love feeding them treats insect football is the best) They have been growing like weeds, they are flying all over the brooder, jumping, running, perching, dust bathing, feathering out like mad, so it is working for us anyway.
It is my understanding the reason for the medicated chick start is so they won't need grit, and to protect from some baby chick disease if you didn't get them innoculated from the hatchery, and for specific protien nutrition needs of growing chicks. Not that the other food would hurt them (at least if they have grit) but may not have everything they need. If I have misunderstood something someone w/ more experience please correct me.