I've got a few posts scattered among the various NoCrow Collar threads that are basically copy/pastes of each other. We received 6 chicks from My Pet Chicken (service by Meyers) back in early June. Supposed to be 6 pullets...ended up with 4 pullets and 2 oopsies. Allowed to have roosters in my semi-rural residential area but I still wanted to keep the noise to a minimum because, while I'm a hermit and take pride in my contrarian nature, I respect my neighbors enough to NOT subject them to unchecked chaos while they're outside roasting marshmallows, raking their yard or otherwise enjoying their various pursuits of happiness. This meant either NoCrow Collars or pot pie for my two boys. We opted for the former.
NoCrow Collars are not for the uninvolved. One of the reasons for my success with the Collars has been that either my wife or I have the luxury of spending a lot of time with my flock. We know their moods/behavior very well. The Collars are not set-and-forget devices. They require observation/monitoring/adjustment to maintain that VERY fine line between adequately-muffled-crowing and choking-rooster. While a choking rooster is a quiet rooster it is also a rooster unable to perform ANY roosterly duties (like protecting his girls) in addition to being just downright neglectful/inhumane/cruel.
Another reason for my success is that I had very low expectations of the Collars' efficacy. I just needed something to take the edge off my boys' bellowing...I didn't want to silence them completely. They still crow whenever the mood strikes them and those crows are certainly loud enough in close proximity to be annoying but at 100' away (and certainly by the time it hits the property line) the crow is a faint shadow that blends in with the suburban ambiance.
Can NoCrow Collars work? Absolutely! Will everyone be happy with the Collars' performance? Nope...observation and expectation-management are key. Can NoCrow Collars kill roosters? Yup, in as little as a few minutes. ANY tool that is used carelessly/inappropriately has the potential to cause great harm.