Galaxyfalcon
Songster
Did she recently take a bath? My ducks will take a bath, splash around, and then get REALLY puffy/ruffled up. Sometimes they get out of their water or get "duck zoomies" and then come back to finish bathing, but they may keep their buffed up floofball mode temporarily. The opening/closing of the mouth could be them getting water out of their ears (I believe) after a bath if so.