what you are describing does not sound like agression to me. My birds peck, and hard! But it is not out of agression, but more out of exhuberant curiosity to see what yummy thing I have brought them.
My speckled sussex Snow used to peck at her hatch mate's toes so hard they would screech...she did the same with pant legs and painted toe nails and finger nails. To me, it sounds like she is just being nosey...maybe try to re-direct her attention. I have used operant conditioning on my birds for various things including pecking too hard! I have one black copper marans in particular I am still working with, but all the others are doing very well.
Give her something to do...she may be bored as well. Does she have a favorite treat? Lay down a picnic blanket, and have a seat. Ignor her or push her away when she pecks, the moment she stops and looses interest in pecking, give her a treat. Increase the ammount of time from not pecking you to getting her treat. Eventually, she will associate "good" behavior with yummy things. Yes, chickens can be trained.