IF he's really that aggressive, and you really want to work with him, get a long handled fish net, and a cage. When you go in the coop, catch him. For me, it worked best if I got him near a corner, and swooped downward with the net, covering him. Do this carefully, and don't wield it with the force of a baseball bat. Now that he's caught, he should settle down, or wait a minute until he does. Slide your hand under the net, while pressing down on his back. Now, extricate him from the net, scoop him up, and deposit him in the cage. Work your coop, with him in the cage, where he can see you. He may get flustered when you are working with the hens. That's ok. Once he's caged, if you want to let the kids in, that's fine. For a couple weeks, let him see you, and the kids working the coop, while he's caged.
After a couple weeks, go catch him with the net, but don't cage him. Keep the net in your hand, as you lightly work your coop. Don't fluster the hens too much today. I usually designate about a 3 foot circle around me, that is my safe space. He is NOT to come into your safe space. If he tries, catch him in the net, move him away from where you're working, out of your safe space. Do this for a couple weeks, until he is always moving away from you when you enter the pen, staying out of your safe space, and staying away as you water, feed, and collect eggs.
When things are going a bit smoothly, catch him, cage him, pick up a hen, and check her over. Let him see you do it. When she settles down, make sure he's watching. Keep a watch on how he's reacting. Is he giving you stink eye? Is he leaning on one shoulder? Do this for a few days, then for a couple days, go back to just catching, and releasing him. After a couple days of catch, and release, cage him, and work with the hens again. When he gets to the point that he looks at you when a hen squawks, but is not flustered, and goes back to minding his own business, eating, scratching, then begin entering the coop with the net in your hand, walking straight up to him, let him move out of your way, and proceed doing coop chores, etc. BE AWARE that there are times, when a rooster has been allowed to remain aggressive to people for too long, and while this method, over time does work, the only time they will continue to be aggressive, is when you try to pick up a hen, and they are loose. I had one that was fine, as long as I was not picking up the hens to check them over. That's the only time, I had to catch him, and put him in the cage. Once I was done checking the hens over, or dusting them for pests, or worming them, I could release him, and he was fine. It was totally do-able. He did continue to improve over time. He was a good rooster, and I had him for many years. We worked out our system, and all was good.
