No he's never attacked her or anyone else before. He is actually one of my friendliest chickens and has never had any issues. She and the other Red have always been top of the flock which is why it was weird he attacks her.
I got all my chickens at the same time in May 2021, 2 were two months older than the other two hens and rooster but they all came from the same farm. They have always lived together and my older two, Rock Island Reds, always ran the flock. My rooster is now obviously bigger than everyone else...