I have one girl who's getting about ready to lay at 4 1/2 months so it's time to switch her onto layer feed and pump some extra calcium into her, but my other pullets aren't quite there yet. I have two that are coming up on three and four months, and I don't want to mess with their health. Would it be okay to go ahead and make the switch from grower, or do I need to wait? They all eat from the same feeder together and I'm not sure how I would seperate them if I really have to.