What makes it not look like a Welsummer? I've had Welsummers before. They have a redder plumage than gold duckwing, and the chick looks exactly like mine as well as the adult.I wouldn't say it's a welsummer either.
Color looks off for that too.
Honestly it would be pretty hard to say for positive what he is.
Any more info about him? Where did he come from? Is he supposed to be a purebred?