Ducks hen's feathers

I noticed today that two of my Khaki Campbell hens have lost the "feathers" on their wings and all that remains is the shaft of the feather...that sounds kind of weird but I think what I am trying to say is there are no fuzzy parts on the feather. (have just looked at a picture and the correct name is barbs or vane....). The other 3 girls (younger and from a different parentage) are ok. Is this a type of moult or is something wrong with them? They seem perfectly healthy in every other way. What could this be? Any suggestions?

yep molt starting. I find mine molt in various degrees but they did that one where the looked like shaft feathers only last summer. Thankfully they grow in fast

I have the same problem ... only for me ... I think it is my Muscovies that are pulling at the Khaki Campbell's feathers ... not sure what to do. They seem healthy.