mean isnt a genetic trait,,,, i have a roo that everyone says how mean he is ( im the only person allowed in his yard) and i have lots of his sons,, and some are sweet as heck,,,, 1 of the worst things you can do is be "lovey" with a roo, even when he's young,, he will take you as another "bird",, and usually take you as another roo,, which, in nature and instincts,tells him that you and him need a pecking order. 1 of you need to be boss,,, and YOU being boss needs to be shown EVERY time you interact with him,, if you walk through the run, and walk near him, if he doesnt back away and "let you through" with a subordinates posture,, then when ya get by him, kick ( push hard with side of foot) him outta the way. if he tries to "mount" a hen while your standing there, go over and kick him off her, and chase him away. after bout a month of doing that EVERY day,, you'll only need to re-assure your boss once in a while ( which means at least once a week).