I bought some chicks this spring - April 2016. They are only 17 weeks so no eggs just yet. I really wanted Mille Fleur D'uccle but was buying from Meyers and they don't sex them. In any case, I now have one hen and one rooster Mille Fleur D'uccle. I am super happy with them. Sweet and cute. But a couple weeks ago, I tried to put a blue painters tape tie on my Polish hen so she could see and when I put her back with the flock, they didn't recognize her. All of her flockmates (raised together) attacked her and the rooster got particularly aggressive and crowed for first time. I had the collar but hadnt' put it on yet, so grabbed the No Crow Collar (bantam size, of course) and put it on (and removed painters tape from Polish hen and gave her a haircut instead... she is so grateful to SEE!) Rooster didn't crow for a couple weeks once collar was on. (I do check collar daily. ) Then the other morning... he crowed again. I tightened collar just a tad. No more crowing for a couple days. I can still get my finger under it. He did get his beak stuck and scratched at it when I first put it on him, but I snugged it up so he couldn't get under the edge. He is now used to it. He doesn't seem to notice. I kinda like the look.... he looks like he is dressed up (I did not get bowtie, but still, can see label sometimes and looks fancy to me - bowtie would be cute). He no longer scratches at it. He doesn't even seem to notice. He doesn't mind me adjusting it when I've tightened it. Maybe he is just a good little roo. He has not been crowing so maybe it is just not habit for him since he has a harem of lovely talkers. Or maybe it is just his age and the crowing will begin in another few weeks. Or maybe this collar really works.
I did read, and it makes sense, to get the collar on a young rooster just before they start to crow to keep them from practicing the behavior. Also, with other new interesting things to distract from collar, might help, too. These youngsters were just starting to free range when I started using the collar so they had lots to do and explore all day that they'd never had before. I think the distraction was helpful.
Another thing that I had read was how to keep roosters from crowing and waking everyone up. So, aside from the collar, you can put them to bed in a "Rooster Box." The box should be dark, though should offer plenty of air and it should have limited height. You want your rooster to be comfortable to sleep, but not be able to stretch up to open airway for a good loud crow. Not sure if it works, but if my rooster ever wakes me up from sleep (or my neighbors!), that will be my next attempt. Haven't tried it yet. If the collar works, perhaps I won't have to. I have never kept a rooster before so this is all new to me. He just needs to be a good little boy who doesn't attack people, rough up his girls, or wake my neighbors. Yeah, I know, that sounds wrong... my poor little roo is not allowed to be himself. <sigh>