I'm pretty sure that if you got a vet to do it they'd do it while the roos are asleep. I'd have a vet do it. I have a Silkie that might be a roo and that's the only way I could keep him if he turns out to be a roo. I live in town.
I had a Silkie rooster while living in town. I raised him from a chick and in all the time I had him, he never once crowed. But he was definitely all male (minus the crowing) as the eggs from his hens were always fertile. A co-worker of hubby's has Silkies and she said almost a third of the Silkie roosters she's raised never crowed.