So you need to get rid of a rooster, right? It's a very common issue actually. It's not about what you need to do, it's about why you need to do it and how you go about it. You don't want your rooster to end up in the wrong hands, but we might not agree on who's hands those are! First, lets talk about the 'why' in re-homing your roo.
1) I'm not allowed to have roosters
2) I have too many roosters
3) He beats up other roosters, flogs my child, and chases the dog.
4) He gets beat up by the other roosters
That's pretty easy, right? Now lets get onto the 'how', however many of these solutions depend on the 'why' for their answer.
1) I'm not allowed to have roosters:
The backyard chicken movement is sweeping the nation, moving beyond the farm to the suburban backyard. Most suburbs don't allow roosters because of the noise. One of your cute little chicks isn't laying eggs and suddenly started crowing! What to do? This is probably still a cockerel, which is probably the easiest to deal with. First, take an absolutely adorable picture, then post him for free. You have several choices here:
Craigslist (farm & garden section)
Put an ad up at the feed shop, food co-op etc.
Take him to an auction or chicken swap
List him for free on local Facebook groups.
You could try calling the local 4H group. They may know a member willing to take a roo, especially if it's a fancy breed....particularly if it's SQ. Lets admit it, most of us that insist on hatching our own eggs order very good stock and what kid doesn't want a started winner. Work you angles here!
This fellow is young. Your chances of finding him a forever home are pretty good. Not many people would get a young non-meat chicken to grow out for meat. It's not cost effective. This is by far the easiest time to get rid of a roo, when their still young and cute!
2) I have too many roosters:
This kind of depends on the age. You can use all the methods in #1 especially if it's still a cockerel. If full grown it gets little tougher. First you need to come to terms with the fact that you really can't control what happens once he leaves your hands. I know you probably want a forever home for him, but people will bluff and straight lie to get what they want. I've seen it happen and it's heartbreaking. If you can't stand the thought that he might be soup, then you're best bet is to search your friend network very carefully and try to find him a home. If he's not aggressive, make sure you mention that too!
3) He beats up other roosters:
This is where it gets sticky. I'm sure that none of us have our heads in the sand. We all know that cockfighting still goes on. Just cause it's illegal doesn't mean a thing to these guys. You have to remember the big NFL dog fighting scandal right? Same thing with roosters. So the big #1 No No is do NOT advertise it as a mean rooster. I didn't say to lie....follow me here....I'm all for full disclosure. I would never lie, but I wouldn't put it out there on the internet for all to see either. You're gonna need to tell a potential owner this in person, on the phone etc. You may not want this roo, you may not care if he becomes dinner and that's fine. Just please don't put him out there for a cockfighting ring. Nothing deserves to die like that. However you do need to let it be known to potential owners that this guy has a bit of an aggression issue. A mean rooster is not going to miraculously reform and sneaking your problem into someone else's yard is just wrong. This is definitely a 'tread lightly' situation.
You could take him to auction. That's sort of a buyer beware situation anyway. Just remember that adult roo's could end up anywhere from an auction. Your best bet is to give him to someone who knows how to butcher or do it yourself. A "free rooster for butchering" ad at the farmers market will probably get you a few calls. If you find a willing butcher then definitely keep their number, you might need it again.
4) He gets beat up by the other roosters:
Ahhh, the other side of the coin. More then likely this guy will mature nicely in a home with his own flock. Again, I believe in full disclosure....you don't want him moving into a situation where he gets beat up by the current roo. You're a little safer advertising this guy on the net although he still could end up in the soup pot. Work your network: advertise on FB, Tweet to your friends, post in your farm groups. I also like Freecycle for full grown bantams. Bantys don't often end up as stew.
If your rooster happens to be a rare breed or show quality you can post him on places like the BYC forum or other chicken/homesteading sites. If there is a forum dedicated to that breed and your willing to ship you might even be able to find a forever home for a mean rooster if he has stellar genetics. It's worth a try!
I'm sure there are other methods and reasons I missed, so if you know of one be sure to leave me a comment! Good luck!