Maybe it's her hormones. I've heard people say that if you separate her for a while (don't know how long) that when she comes back she'll be lower on the pecking order and this may correct her bad behavior.
It's dangerous if she's making them bleed because the others will see the blood and may start pecking at them also. I would put something on the bleeding areas (i use Pick No More) to camuflage (sp?) the blood spots. It also tastes really bad. (it's all natural with pine tar and other stuff)
I'm getting a little coop that holds 2 chickens that I will be putting right next to the regular run so that I will have a place to put an injured chicken, one that's being a bully, or one that's brooding and hatching chicks. This way, they will be seen during separation and have an easier time (hopefully) when I re-introduce them back to the flock.