Black shoulder had to come from somewhere at sometime,,yes?? And I doubt when the first b/s was hatched by a peafowl fancier many moons ago and being all white-yellow at birth they knew exactly what was going on either. My guess is every pattern and color has to be present somewhere on the DNA otherwise how does all these new found colors emerge???
This is what I love about genetics! Unfortunately, without hybridization, genetic improvement is not usually possible. DNA is like a long series of light switches, if the right ones are turned on (or off), then the results can be different colours or deadly genetic disorders (cameo "death" gene). Some of the origins of blackshoulder peafowl are unknown, and many believe they originate from hybridization with greens. I don't know if this is true, but it seems odd how the chicks come out a completely different colour than spauldings chicks do.
I've hatched 2 white b/s chicks from my IB pen this summer and the lone IB/BS male in this pen was the last one out of 3 males pecking order wise.Early in the season I thought I was going to have to pull him out because he was getting chased all over,,,,but some of the girls must have liked him.Sent 15 IB eggs to a man down in southern Illinois and he hatched 2 all yellow chicks too,so my IB/BS male was seeing some action,,,but again about b/s,,,I'll just bet the first b/s peachick ever hatched (whereever that may be) had two barred patterned parents.Somewhere the b/s gene snuck up and hooked up correctly and viola!!
I am reminded of some nature programs with this. In lions, for example, lone pairs of males will often roam and sneek in to mate with females of different social groups. I believe that yoda's bird could very well be a peach, even with a young split male in a pen of older ones, just like the senario described above, all it takes is one time.