Quit giving him treats and he will eat the chicken feed, I can just about guaranty it.
I will also guarantee that you rooster will see the light after a few days. Roosters are also bad to feed all the best or choices pieces of feed to their hens. Add in the fact that
"roosters don't lay no eggs" and it is perfectly OK to nix the table scraps. That left over T-Bone steak is one possible exception. Just cube it up finely so no one gets choked and every one gets a share of the goodies.