Starter up to 8 weeks
Grower from 8 weeks until you get your first egg
Layer from first egg on.
I agree with the other posts. I have RIR's too. I use starter/grower until I get my first egg then I switch the girls to layer. I personally use crumbles. I tried a small bag of pellets but they didn't seem to eat it to well, so I switched back to crumbles, but I started them on crumbles. I smashed up the pellets and mixed it with their crumbles. I have some new baby girl RIR's that are 5 days old. I have no Roo's. If I have any starter/grower left when they start laying, I mix it with the layer until it's gone. I haven't had any problems with my big girls laying. And I did the same with them. I personally use the medicated starter/grower.