One of my 11 sexed girls 1 turned out to be a roo. Because of crowing i cant have roosters. I wanted to try one last effort before i gave him up because i really love him. Hes almost 5 months old now and a gentle giant. Hes a silver penciled rock and just beautiful. Hes already about 5-6 pounds and is twice my barred rocks hight. Hes good to the girls and good to my family and a gentle breeder. So i i did was order a no crow collar for his size. Thank God it works!!! It really works!!!! When i can hear his crow its lower than the cluck of a hen!!! Im so happy! I know people have had mixed results with this but in my case it proved 100% effective!! I can now keep "big daddy" and im very greatful!! It took some adjusting on his part to the collar but now it does not bother him one bit. Hes able to eat, drink, breed just not project a crow anymore. Im so glad i tried because i didnt want to loose him! Just wanted to share with you all. Im so happy!!