I'd really not worry too much about the black flecks in the down. Unless you've introduced new blood recently, the genes responsible are most likely part and parcelthanks
i'm worried about the black spots but hopefully they will disappear when they get their true feathers. I think i'll cull them from my breeding flock anyway.
of the larger sum. In other words, and in my opinion, they'll have no discernible impact after the down is lost, and should be ignored.
Kind regards,
Kevin