The laying pullet can eat their medicated starter until the new ones have been outside long enough to no longer need it. They need to have been outside exposed to the soil for at least two weeks while eating medicated feed, for the medication to work and help their systems build immunity. So everybody can eat medicated starter during that time, and until they finish the bag (no need to waste it if you have more left after those couple of weeks are up). And after that, you can put everybody on an all flock type of feed, with calcium on the side (oyster shell or eggshell) for whoever is laying. That's what I do when I have new chicks. And even if I don't have chicks, my flock always eats an all flock type of feed (in my case, Purina Flock Raiser) with eggshells on the side. I've never used layer feed, I don't like the idea of it already having extra calcium added, because chickens' calcium needs vary throughout their lives and through the seasons, and they should be able to regulate how much of it they eat.