Probably a mixed breed, my guess is silver laced Wyandotte crossed with buff Orpington. It is also possible it's a Colombian Wyandotte but the legs don't look yellow enough in your pictures. So it depends if it's supposed to be purebred or not.
It’s my first rooster I’ve seen of mine to do a mating dance type thing he stomped his feet ,puffed up, then put his wings tight against body and straight down.
He's beautiful. The nice thing about mixes is that usually each bird has a unique look. If he's doing the mating dance, then that is often a good sign, and he will probably be a gentleman to his hens.