All of our chickens arrived on Sept. 1st making them just about 6 weeks old. They are growing soooo fast. I think we're feeding them too good! So, in the last week, they have all passed from the mangey looking stage into having complete feathers all over including up their necks and all over their heads. But, now something weird is happening we can't identify. It's not with all of them, but with more than one. There's a group of feathers on their backs starting to bunch up making them look kind of hunchbacked. Is this just a normal growth pattern that we haven't seen yet, being newbies?