I prefer a mutt to a purebred chicken. There's a lot to be said about hybrid vigor. New, unrelated genes usually produce a better offspring. One of my favorite crosses was a Production Red roo to some commercial white leghorn rescues. The chicks were GORGEOUS, strong, and super healthy- until a fox attack. Fortunately I'd given some to a friend and they were his best chickens ever!
Right now I've got some red sex links, production reds, and australorps- will be crossing the australorp roos next spring with the reds.
Previously I hatched some eggs that were mutts- Mom was an ee/wellsummer and dad was an ee/silkie. The chickens were beautiful, great layers, and some of them had the 5 toes and black skin of the silkie. They laid beautiful olive colored eggs.