How good are the no-crow collars for roosters?

[farm316]

Thinking about getting a no-crow collar for my rooster. though on Mypetchicken.com it is 22.00 dollars.

Do they work? Or not? I don't want to blow my money on something that will not work!

 

[HighStreetCoop]

There's a long discussion of them here:

https://www.backyardchickens.com/t/906916/no-crow-rooster-collar

They work for some people/roosters, don't work at all for others.