Just give them all flock food. You don't want your egg layers getting any of the medicated feed. You don't want chicks getting layer food, but all-flock is fine. And at 10 weeks old, the regular grit is probably good, but you might leave some smaller just in case.
This may go without saying, but if you're feeding all flock, be sure to provide an extra calcium supply, free choice, for your layers (crushed oyster or egg shell).
Thin shelled eggs are no fun.