I'm wondering if my barred rocks are younger than what the feed store lady told me. They are supposed to be around 15 weeks old, but they are smaller than my other girls were at that age, and just today I noticed two of the three traded in their peeps for clucks, which is later than the others did as well. Also, the one who's still got her baby voice is noticeably smaller than the other two. I'm assuming that barred rocks are supposed to mature as fast or faster than orpingtons and wyandottes, and that my runty chick is actually slightly younger than her broodmates. Anyone want to venture a guess?