I never play or mess around with cockerels. Heck, I really don't mess around with pullets, either. You'll still get some bad apples. Most chicks, you either don't know the breeder or they're from hatcheries, which are not breeding with an eye toward temperament at all. I believe that if...
Sometimes it's quite early. But you simply can't look at every 6 month old male that isn't flogging you and think, "Great! This won't be a problem." because........sometimes it is.
Every one I've had turn bad went before 18 months. They will seem fine and then BANG. The last one I put in with some pretty mean old hens that gave him what-for and he was the worst I've ever had.