The hens are the problem. He thinks he has to protect them and he thinks you're a threat. What you need to do is two things. First thing, most important, is to establish you're in charge. Do this by body language, show no fear, never back up, always make him move out of your way, and when he comes at you in the aggressive manner you describe, you need to discipline him. Do this by quickly, in a single motion, stooping and pushing him flat on the ground with his head pinned. If you can grab and pinch the skin on the back of his neck at the same time, do it. Hold him there until he calms down and goes quiet. Repeat this every time he charges you. It shouldn't take but a day or two for him to get the message.
The other thing is to develop trust with him. You do this by treating the hens calmly, no sudden, loud moves. He's worried you'll mistreat them, and he needs to learn you won't harm them. This will take more time than the discipline, but he'll come around as long as you're consistent.
There are always a few roos who are belligerent and nothing will change them. But even those usually calm down with age, and by the time they're two or three, they can be pretty nice guys.
