Talking to breeders would be a good start. I've had a few hatchery roos, and have picked up many, many roosters for people who have had aggressive roosters of all breeds. Right now, I have an older hatchery RIR who is a very good guy - very good with the hens, good with people (avoids them), and doesn't freak out when my kid (4 y/o) runs through the flock when they free range. I think he's 2.5 now? I also have a year old breeder quality BLRW who is very, very calm, good with his hens, and tolerates handling very well by the same 4 year old (she likes to pet him, he doesn't care - the RIR keeps away from her).
I started with 12 chicks when I got back into chickens, 5 of which were roosters. The RIR is the only one left - the rest were sent to the freezer when they either challenged me, over bred the hens, or thought about chasing my kid. The BLRW I picked up from a breeder last December along with a batch of other non show quality culls (she knows I process them for food, and is comfortable with that).
I think it just depends on the individual, but breeders are a good source since they are aiming for high quality instead of producing masses of chickens. My BLRW is very calm and gentle for being an adult roo, and though I don't let the kid out unattended with the chickens, he behaves very, very well when she is out (and I'm right there). All of the hens (I'm up to 19 now) do not have bare backs and are happy.
