Missing pigmentation on some feathers

[Daisy8s]

My silver-laced wyandotte hen came through molt and turned up with all-white flight feathers on one wing--just 6-8 of the longest feathers are solid white instead of edged in black.

About the same time my barred rock rooster developed one white feather in his tail--just the one feather at the top of the curve.

I have two bantam Australorp hens...one molted and grew back all black feathers like usual, no missing pigmentation.

Any thoughts on why the two would be missing black pigmentation on just a few feathers?

Background info: I feed a layer mash from my local mill, plus a bit of either wheat sprouts or fermented scratch every other day. Nothing has changed regarding the feed except that it's winter so when it snows they go into a covered run that doubles as my compost heap where I did put in a lot of horse manure last fall. Don't know if this is useful info but I'm disclosing everything I can think of.

The whole flock is healthy, good shiny feathers, no parasites that I can see.

Any thoughts on why would be appreciated. I'm not worried--they're healthy and not show stock. I'm just curious and would fix a nutritional problem if this were a sign of it.

 

[JerseyGiantfolk]

Occasionally when chickens age their feathers won't be as long or have the same tight and/or correct markings as the used to have. Usually utility birds will not have correct markings as a breeder bird would.

 

[Daisy8s]

Oh, I should've mentioned that both these birds are 11 months old right now so I didn't think age would be a factor.

And, yes, they are both hatchery stock.

I just wanted to rule out some kind of nutritional deficiency if that was possibly the factor.