I am not sure if this is the current advice, but it worked so well for me I always do it.
Are you training him to see you as dominant? I'd say it's probably harder once they start challenging you, but I had to do it with my first roo and it worked. I had raised him like a pet, which I am now of the opinion isn't good with Roos.
The best way I can explain what I do - act important and purposeful. Walk where you are going like everyone better get OUT of your way. Walk to a point beyond him, so that he's in your way. Act like you're going to walk right over the top of him if he doesn't move out of the way. (And hope he does ... mine always did.) Every once in a while, chase after him, let him run away, maybe chase him a few more times. It is always best, IMO, not to have to defend yourself but have him respect you from the first. Besides, I'm thinking if he's purely attacking and you're purely defending, he's probably just feeling even more like the boss. I had to scare the heck out of my beloved little Japanese Bantam when all 1.5 pounds of him decided he might be able to kill me ... and I had to teach him manners without hurting him too (tiny thing!), so the only way was to make him THINK I was going to hurt him.
Oh, I almost forgot. A few times I did pick him up and flip him over, holding him by the legs on the advice of chicken folks. I never liked doing it though, and was afraid I'd hurt him. His pride at having it done in front of the ladies seemed to be hurt, he'd sulk away and hide for a while, so maybe it was helpful.
But the walking thing accomplishes a lot. You might also bring a few select treats for the hens, but chase him away and not give him any. I know it sounds mean, but it gets the point across.
And if there's some new advice, I hope no one gets offended at what I've said. I know dog training goes through trends.
