My khaki campbells have been developing these whispy thin feathers on their backs. They are not part of the wings but the feathers that lay over the flights when the wings are folded. They seem healthy and are active and the other ducks don't seem to be having any troubles. Is this something specific to campbells or are my girls lacking something? I hope you can see what I am talking about, the rain has made things clump together a bit. Click on the pictures to get a bigger view.