What happened when we put Cockerels in with hens?

That was one nasty rooster. I had a flock of 7 girls and 1 rooster who wandered in. He was welcomed by the girls, & he's a gentleman. He does mount a few times, but not aggressively. He's more interested grazing and staying alert and watching for predators. And when one of the girls is sqwaking, he runs over to check if everything is ok.