I have 13 chickens that are 18 weeks old. One of them started laying eggs this week, but the others still aren't. Should I switch everyone over to Layena? Will it really matter if the one that is laying continues to eat the chick starter for a couple more weeks? At this point, I still have about 30 lbs of chick starter, so I'd rather just let them eat that (probably will only take about 2 weeks) then just switch them all over to Layena, but I didn't know how much of a difference it would really make. Advice?