I have a group of ducklings that were born the last week of November. They are a mixed bag of WH, runners, and buffs. They feathered out nicely a couple weeks ago, but I started to notice that some were missing feathers right along the breast bone. Now I have a number of them who have nothing but down on their entire chest. They are the most crazy, nervous batch of ducks I've ever raised. Could stress in ducks cause chest plucking? Could this be some kind of parasites? They are housed right next to my adult flock and none of them are showing any feather loss. Any ideas? Thanks!!