I agree with Amy - it's in their nature, especially at that age, to try and establish dominance. I've found that most of the young boys go through a fairly aggressive stage with both the hens and other males during this time of their lives and often settle down as they get more mature. Very sorry for your loss - he was a very nice boy, but the back up roo also looks really nice. It IS very hard to find a nice black cockerel so I'd sure hang onto the second one (pm me if you would like someone to take him off your hands!). My senior buff roo killed another cockerel when he was young, but is not at all an aggressive bird now - fine with me and the ladies. I often wonder if maybe these things are a fluke - perhaps one got the other in a type of chicken choke hold. I lost a hen some years ago that way - think she just got held in the corner with face into the ground and she suffocated
Overall though, I think silkie boys are much less aggressive than a lot of other breeds.
