The name Pioneer was give to their birds and McMurray stated on their site the name in the industry is Rainbow Chicken, however I know that Hoover Hatchery has them https://www.hoovershatchery.com/rainbow.html
The old fashioned birds were like the Rainbow, good utility and early maturity, hatcheries and even show bird breeders no longer concentrate on the utility aspect and so the dual purpose breeds are basically pretty birds now a days.