I had to rehome one roo over the summer, and had good success with advertising him through farmers groups on Facebook. He ended up going to a 4H girl who showed her flock. She took him to the county fair and he won!
But I was super selective because most of the people who were interested in him wanted him for meat or cock fighting (they didn't say that, per se, but it's a thing). So, yeah, there's not a big market for extra roosters, but I'd try FB. :/