Black spangled pumpkin? Red quill? Partridge black red? Mom is Ga Noi/wheaten American game, Dad is BBR Asil. His back is the color of his hackle, Picture doesn't do it justice if you see him in the sun.
There is bound to be a name to use for color description. There are plenty of people that raise birds that don't come in a set color pattern, so it's bound to have happened before.