I use Flock Raiser myself, but I wouldn't put my chicks on it quite so early. I generally begin to transition then over from chick starter to Flock Raiser in the eight to ten week range. I feed greens, but keep the scratch and all other treats to a minimum. Usually I broadcast some rolled oats over their bedding every other day to encourage them to keep it scratched up and fluffy. Just a handful or so, not a great deal. They need to be getting most of their calories from the starter feed.
Chick starter, Flock Raiser, and all other sorts of finely ground feeds don't need grit. They're already finely ground. It's only when you begin to put foods in that you yourself would need your teeth to chew that they would need grit. Usually I start giving them grit when I start their green feed at one week. It's just coarse sand sprinkled over their starter like I was salting food.
I use Flock Raiser once they are out of the brooder box and feed it right on even when they are laying because I supplement with ground oyster shell. If you want to use layer feed I wouldn't start transitioning the birds over to it until you see the first eggs. Start blending it in to their feed until the old feed is used up. No point in forcing them to eat a lot of calcium they don't yet need. I'd still offer oyster shell on the side because some birds need more than others but if they can only get it from their layer feed they'll eat extra feed just to get it which can make then unnecessarily fat.
