Finally getting my chicks!

I have been wanting to do this for over a year, and I orderd 7 (Isa?) browns from a grain elevator, picking them up this week sometime. I have been reading and reading this site and I will continue to keep reading, but I am having difficulty finding an answer so I am hoping someone can help me with this.
I do not want to feed my chickens commercial grain. I know this will mean more work for me, but I am very adamit about this. I am trying to figure out for the new chicks what is the best combo of foods to feed them, and how much grit they will need. I am having a bit of trouble finding this because everone (or what I have read so far) uses the grain. If anyone has a link for me or any advice I would so appreciate it!

The reason I dont want to use the grain is GMO's incase anyone thinks I am crazy for not using grain! Organic is not so urgent (but prefered) I just want to do this as natural as possible. I have heard that cooked brown rice is good, and cooked oatmeal, meal worm or other bugs, greens such as veggies (broccli, califlower, cabbage ect...) is this a full diet for chicks?

Thank you!

Sue