Well I believe you're all correct unfortunately. He's just started doing a bit of rooster fighting with the baby silkie cockerel I have for my flock.
Definitely a cockerel, but not because of that behavior. Pullets will spar just like the males do. Some even whip up on them pretty good, too!
I didn't know hens did the neck flare, raptor style lunging thing. I have a dominant hen who's terrible to all new comers at first but she's more of a chaser and pecker of them as opposed to jumping and neck flaring. It's fun to watch them all interact. Such a complex society chickens can be!
wow! She sounds terrifying haha! I'll bet she's at least entertaining to watch!