I have heard of production blues - interesting to understand what they are.Ran across an interesting tidbit while puzzling over lil' blue. According to that bit, any black can be turned blue through the BBS breeding principle. Somehow I can't quite see a buff brahma with a blue collar.... and I don't think the Colombian marker and the BBS color can cross. However, I'm not a geneticist and I suspect trying to figure that out would require some serious gene mapping. Another odd cross I encountered is the Rhode Island Blue (aka production blue): Rhode Red crossed with black Australorp. Unless the RIR carries the splash hidden under the red, how is that even genetically possible?