Are the two related? On average, roosters are meaner to their sisters than any other hen. Is the hen broody? Sometimes if this is a new thing, that's just a sign of her going broody. Other times, she's going broody to get away from him. Is the hen otherwise healthy?
I would get rid of the rooster (cull, give to bachelor flock, tick control), as once she's gone for awhile, he very well may go after another.
I had an EE rooster that targeted my Buff Orpington/Buff Brahma cross named Nalla. They weren't related and she was healthy. He attacked her so bad that he first left deep holes in her back (before I knew the issue) and ripped her neck open in a single peck (that's when I knew he was the issue). I had separated her before I realized he was the issue and while she was away, he started pecking a hole in another hen's back. When Nalla healed, I returned her to the flock and was shocked to see her so scared of him. When I caught her and brought her to the (non-people aggressive) rooster, that's when he went after her neck. I quickly removed him from the flock, and after a few days I had given him a few other hens and one went broody just to get away from him, which was another display it was him, not the hens.
One these three hens, I later introduced them to the rooster's son (this rooster hatched before he started attacking Nalla). They all did great with the son, and after keeping Nalla for a few more years, she did excellent with other roosters as well. That first rooster was the only issue. On the son, he was no issue with any others except for with his sister, which was no more than a little bullying that wasn't noticeable unless you knew the two.
she screams if I even get near her
