One of my ducks is making a continuous whispy sort of noise and is constantly open her bill to let the sound out. Her whole chest area seems to be heaving. I don't recall that she was breathing like that this afternoon. She's been active all day. I went out to run an errand and then came back and gave everyone some food and lettuce. A little bit later, I noticed she was making the strange, continuous noise and then opening her bill constantly. Does anyone have any insight?