I agree with many of the others that have replied. DON'T DO IT! If you don't like it, rehome him. It is better to do this, than to make him live a life of pain for doing what he is born to do.
In another post, by Choco Maran, it was mentioned that they didn't understand why someone would ask why someone had a roo since many get some they don't want and this makes sense. It happens. People are going to respond in different ways when this happens. Choco Maran chooses to keep hers and to treat them as a part of her family. VERY commendable as many don't. It is also mentioned that Choco Maran wouldn't get rid of hers/his or cull them but she/he takes just as much care of the roos as the others.
I guess what I am trying to say is that if you aren't willing to let this rooster live a natural life then the best thing to do for it is to rehome it. I am not too fond of rehoming but when there is no other choice or the alternative is a shock collar rehoming is the best you could do for him.
I don't understand why a shock collar
would be an option at all but I am against using them on dogs or any other animal to begin with so...
(Choco, I hope no offense was derived from this as none was meant or even implied
but sometimes when typing that can be how it comes across. I was trying to compare how you handle extra roos to how others were contemplating handling it.)