I have heard each color called a breed? I dont understand that, guess monkey see, monkey do... I guess the proper term would be cross-variety....Yes, I was remembering wrong, you can cross BBs and Spangles and get more of the same, but then BLOOD wise, they wouldnt really be either, it would take three generations of further selective breeding to have either color pure after making that kind of cross....I know that a lot of people that breed spangles will after so many generations have too much white spangling in their birds, and they go back on the BBs to fix it...but then they selectively breed for several more generations to get your birds pure spangle and/or BB....some people cross colors all the time, thats how you get the Golden Duckwings, but then those birds will not breed true....some do it all the time, and some wont breed different color varieties through a desire to keep their birds pure...or they breed different colors in as seldom as possible...