SDJIM, that pheasant is referred to by game bird breeders as a Buff ringneck (they also have Red Buff and Buff Isabell). Other changes in the color phase of pen raised ringneck pheasants includes Melanistic Mutant, Pied pheasants, Auburn pheasants and many others.
All of these changes in the natural color phase in pen raised comes from years of inbreeding. And is definitely a sign of domestication. I personally would not release them into the wild.
The Melanistic Mutant pheasant has various darker color phases but those changes in the mutant pheasant color comes from years and years of pen raised inbreeding of other ringneck pheasants. These mutant pheasants were not seen in the real wild natural pheasant world 150 years ago. The Melanistic Mutant pheasant first showed up in Norfork England pen raised stock in the 1880's and by 1930 was seen in North American pen raised stock.
Look at these authentic wild ringneck pheasant (P. c. Torquatus) in central China, below. You will not find Malanistic mutants nor Buff pheasant in the wild out there. Note the yellow iris on both the wild roosters and the wild hens and the wary and alert disposition:
http://wntvapple.blog.163.com/blog/static/16586197020101097222853/
We need to get more of these authentic wild pheasants.