Well this has certainly been couple of days of discovery.
After taking about hundred 'smudgy' pictures of very uncooperative hen, I went thru them quickly to narrow it down before downloading. After erasing most of them, it occurred to me that several had whitish smudge around the head, so back to the barn I went and sure enough, she has 'whitish' ear-lobes.
This hasn't really been obvious before, but about a month ago I have put a cock in with the hens and they have been lovingly 'grooming each other, so everybody's muffs are becoming sparse.
So I guess that gives me a pretty good idea of where the good Blue color comes from.
I doubt I would have noticed it, if it wasn't for this forum help, well worth the price of admission. thank you.