You can put a soft cloth collar on the rooster and it will mute his crowing, plus he won't want to crow so often. Apparently, it can cut the noise and frequency by more than 75%. The collars can be bought online but you could also sew your own. It fits around his neck snugly but not tight. When he wants to crow, he'll feel the pressure on his throat and won't want to crow as it will be too uncomfortable.
