Temperament in a chicken is passed down to the progeny the same way as body type, leg color, plumage pattern, etc. You absolutely *can* breed for good temperament in a rooster and I do it successfully. <br /> Nothing is 100% foolproof-after all, you are dealing with an animal with a small brain, not a manufactured product, however, 99.9% of the time, every male that comes from my heritage line of Barred Plymouth Rocks is easygoing and non-human-aggressive. <br /> No amount of "aversion therapy" will permanently change a human-aggressive rooster whose genetics have programmed him that way. Does not matter if you handle him as a chick, or don't handle him as a chick, genetics will out. Aggression is also a function of intelligence in my experience over the years. You don't breed stupid. Breed the best, cull the rest! <br /><br /> Hope this helps someone who is trying to understand their rooster's behavior.<br />...<br /><a href="https://www.youtube.com/watch?v=atJpuOv49XM" target="_blank" rel="nofollow">https://www.youtube.com/watch?v=atJpuOv49XM</a>