Right! The chest bumping!? Mine are 2 weeks old, and I saw them doing this today! All females, all about the same size. Out of ten, there is a Cream Legbar and Choc Orps who are leggy and larger. Then I have two Golden Cuckoo Maran (I THINK!?) Who are considerably smaller than the rest of the average sized. The GCMS are much more timid and shy, but they get thier whoops in too. The chest bumpers were a Choc Orps and an unknown. And they came with a packing slip!?
They also like to do this jump/fly move, resulting in chicken bombing a predestined target. Many times the target is at rest, but not asleep. Is this normal pecking order? Is it like puppies? Everything works out as long as someone gives up?
The chest bumping is hilarious. They remind me of little angry high school boys.