This seems like a very difficult moral question here, and I’ve noticed that it hasn’t been mentioned here yet, but any procedure like this has to be done while the bird is awake, anesthesia is extremely dangerous for chickens. Not my personal cup of tea, I love my crowing roosters, (like the person above said, I can tell each rooster apart by his (and her) crow) but to some people de-crowing is a preferable alternative to culling the rooster. I’d say do as much research as you can and decide if what the procedure calls for it truly in your birds best interests. Best of luck