The blind blackcock is coming out of his moult more everyday. It’s interesting that he’s got some really prominent white feathers on his neck, and there is almost an entire collar underneath his chin. This seems to be a characteristic of birds coming out of the moult, and I’ve seen them as late as November. Similarly, the white eyeliner is one of the last signs of the moult to vanish, and this is also obvious on greyhens as well. Perhaps greyhens get the white speckles on their chins too, but it’d be so hard to tell with abird that is cryptically marked at the best of times.
I have sometimes seen stuffed blackcock with white feathers on their necks, and always used to wonder why they were there and what they meant – it’s just a natural quirk and I suppose there are no particular advantages or disadvantages to it.