How about if you just mix the grower in with the layer feed? That way, the babies can have their crumbles, and the layers can have their food. I've read that if the non-layers are eating the layer feed, they can get too much calcium and it can prevent them from laying or cause them to have problems with laying.
I would do what Hangin wit my peeps suggested...give them all grower and then provide oyster shells to those who need it. So far with my group, the only ones who eat the oyster shells are they layers. The other girls completely ignore it.
Try both and see what happens. Let us know!
~Caran