I have 2 healthy 14-wk-old Pekin females. When I approach the dominant one to give her treats, pet or pick her up, she trembles...mostly just her neck and head. It looks like fear/nervousness/chill, but I really don't believe it is. She does it especially when I sit outside and she nibbles on my clothing. I think she might be preening me? Is this behavior something ducks do to each other? The other thing I wondered is if it could be a dominance thing. I have seen the less dominant duck do it, but infrequently. Is she just excited or happy to see me and to get the treats maybe? She does it even when I don't have treats. Both of my ducks are very tame; they are outside all day and are locked up at dusk. They usually come looking for me at dusk because they still won't go in their house without me picking them up and putting them inside. Silly ducks! They do like their consistency and routine!