I live near Meyers hatchery and they have Poultry 27 (27%) I was able to order Kent formula from them who also has a 27% and a flock raiser at 18%. which I will be changing them to in a week.
I used crumbles made locally that were non-medicated, all natural, just mixed grains. Worked great. I personlly wouldn't off "foods" at that young of an age myself. Keep it simple, fresh water (I use filtered) and grains. You can add treats laters, fruits, veggies, etc., mine love rolled oats!