The most important thing, regardless of how you treat your roosters, is that you cull ruthlessly. Aggression is often at least partially inherited. Hatcheries worry about egg production, not temperament or physical appearance beyond the basics. Some breeders, likewise, will keep aggressive roosters. If you cull aggressive roosters ruthlessly they cannot pass on their genetics, as the generations continue aggression will eventually be all but eradicated.
That said, there's pretty extensive documentation among other species that an animal -- birds included -- that are unfamiliar with being in your personal space will require much more motivation to put themselves in close contact with you than those who are well accustomed to being in close contact with you. IOW, a rooster, gander, drake, tom, etc that has not been coddled will be far less likely to see you as something he should/could be challenging. And if/when he does he's more likely to retreat with less pressure from you to do so. We do not coddle.
I might throw a couple dozen in with my next hatch.
