I agree with the comment that not everyone can be present in handling animals properly. If you've read my blog, you've read my rant about domestication and how that means we have an obligation to be constantly present in our animals lives, but some people simply cannot comprehend that. However, with your family, do press it that it takes a village. EVERYONE has to be on board to make a happy, healthy family, and our animals - pets or not - ARE our family, and we need to spend time with and be consistent with ALL OF THEM. Cesar Millan, the dog whisperer, has stated multiple times when a family is dealing with a problem dog, but only one person is willing to be receptive to him, that he can't do ANYTHING until the whole family comes together. EVERYONE must be consistent, and above all else being consistent and patience is what's important.
Also, will there be a day you won't have to worry about him suddenly becoming aggressive? I will only answer that as "possibly". You need to constantly be a part of your animals lives, and you CAN make it so that they're happy, healthy, and non-aggressive, and chances are they'll stay that way. HOWEVER, if you stop being alpha, and you stop asserting yourself, that animal is going to be left with a huge hole in their social hierarchy that, to them, MUST be filled. Animals don't understand passive social order like we humans like to play, they only understand dominant and submissive, leader and follower, so you must always make that known. However, once that's clearly instilled in their minds, it IS much, much easier to maintain.
That being said, the chasing is a difficult thing to curb. I still have to chase down some of my roosters, but I use my whole body, and sometimes a hockey stick, to "herd" them into a corner. I can pretty consistently get them into a corner of the fence, or between a couple trees then scoop them up from there. Once I have them cornered, I make sure they can't get away, but then I descend on them SLOWLY AND CALMLY, wrap my hands around their wings, and gently pick them up so that the process of being picked up isn't one of unhappiness and fear. Unfortunately, with chickens being prey animals, unlike dogs and cats, it's a little more difficult to train them to come to you, but you can always make the actual event of BEING picked up one of pleasantness.
That being said, I think making a corral to herd him into is a great idea. Make sure it has a wide opening, because chickens can easily sense enclosed areas and doorways, and perhaps even make a funnel up to the entrance. I've had a lot of luck using funnels as opposed to obvious doorways. Chickens also like to stay near edges of things, like the edge of a fence, the trunk of a tree ( I can't tell you how many times I've chased a chicken round and round a tree in the middle of an open area ), or the wall of a building, so try making your corral in a way that it incorporates something he already likes to run near.
