I have 4 Barred Rock pullets. They are currently 10.5 weeks old. I won't run out of starter feed for another couple of weeks. My question is, can I just switch them to layer feed at 13+ weeks or do I have to feed them grower feed? If I get a bag of grower feed, that should last me Through June. Will this inhibit egg laying? I anticipate them to start laying towards the beginning of May. A little confused and don't want to waste money of unused feed.