We currently have 7 Orpington Roos. 2 Lavender, 2 Blue, 1 Black, & 2 Young Buffs. As far as crowing I cannot say ours crow a lot. Just heard one of the Blues (5 Months) the other day and he wasn't very skilled at crowing as of yet. Still haven't heard the other Blue yet.
Our Lavender "Diva" is our oldest and he only crows when startled, the same with our other lavender Roo.
"Diva" is our tamest, then "Hansel" (our other Lavender), [Probably because the Mrs. and I spent a lot of time with them, almost to the point of house pets], then would be our Black, the 2 blues, and last but not least the Buffs.
There are a total of 10 Roosters (Most are young yet) in our flock, not counting our separated ones. "Diva" is the oldest and also top rooster, "Hansel" a close second, then would be our Ameraucana Roos, and the Blues and Black quietly in the background.
As far as mating, "Diva" is quite the suitor when it comes to the hens. He does his special dance and if the hen squats, then it's on, otherwise he just walks away. "Hansel" on the other hand is more of an opportunist, except for when he's courting our Lavender hen "Gretel". I have never seen him more than 10 feet away from her and he protects her from all the other chickens in our flock.
As far as predators, I have seen both our Lavenders patrolling the fence whenever a cat would walk by. When our puppy (Black Lab/Blue Heeler/Border Collie) and I go into the pen, "Diva" and "Hansel" both keep a close eye on him and if he gets to close or tries to "play" with a chicken, they surround him pretty quickly.
We haven't had our Orp Roos long enough to tell if they are aggressive, but we doubt it.
We highly recommend Orp Roos!