I once had a rooster that stalked 2 specific hens. They were free range, and there were over a dozen other hens for him to choose from, but he consistently went for those 2 hens. He'd try to mate them, and when they resisted he'd just attack them. I tried separating them, confining him, confining them, getting more hens, pretty much everything I could think of. He just wouldn't leave them alone--I'm talking they would spend their days hiding under the porch with him standing on top of it, waiting for them to come out. For hours at a time--I had no idea chickens had such an attention span.
I eventually butchered him, couldn't figure out what else to do. He was fine with humans and the other hens, just psychotic about those two specific girls.
