With my flock, the top hen (Spindrift) glares down my favorite hen and gets in her face (Zelda) to somewhat intimidate Z. If Z doesn't move then Spindrift delivers one swift peck to her noggin and Z immediately moves.
Spindrift's inseparable best friend Morticia is lower ranking than Zelda and I've noticed on more than one occasion Z pecking / running M away from treats if M gets close to Z. But Morticia doesn't get pecked by Spindrift at all - they are always right next to each other like conjoined twins almost. So the lowest ranking hen paired up with the top ranking hen in my flock.
I'm not sure if this makes a difference but Spindrift is one week older than everyone else. She is definitely my rooster's favorite and he will stick with her more than any other hen (also try to mount her a lot more than he does the others) - however, if any one of the other hens does a distress cry or frustrated egg song when they are free ranging he will go running to them, leaving Spindrift (but he is quick to return to her if he sees / think everything is fine with the others). Spindrift is also pretty much always the first and only hen to get whatever treat he signals at, which further confirms my suspicions that she is top hen.
It took me a while of actually observing and watching all of their interactions before I finally established a pecking order because all of their body language / communication is so subtle at times. Also Zelda is a real loner chicken and doesn't interact with the flock much so she was always the questionable one where she stood within the ranks.