Fighting Bantam

We now have to keep our small Bantam away from the other hens-  she goes in fight mode within seconds-  she has always been crossed with a Pit Bull and a bad tempered bird!  She has hatched some hens, even they do not like her now! She fights the other big hens through the fence and gets a blood (y) face at times.  Poor girl is now in a fenced off bit and looks like she will remain there until she dies.  I refuse to go in to get her egg-  she always flies for me- she leaves my husband alone-  this evening she got out when he went in to collect her egg, within seconds she was in a fight with 3 different hens.  Her name is ´the Rottweiler´ 

How can such a tiny bird be so scary?

Pamela