Puffed up ducks.

[FluffTheDuck]

My Drake's do it whenever I'm by them, they do it when they're happy like when i gently pet them and when i feed them lettuce etc.

 

[FluffTheDuck]

My boys do this when I come hang out with them, and then they do their grunt-whistle and zoom!

Same here

I just call it "puffy"--
"Look! Huey is being SO puffy right now!"
I love that word lol.

 

[Miss Lydia]

 

[BjaJra826]

I love it! My dominate drakes do this. I used to call it breasting up but totally switching to puffy ducks lol

 

[ded73503]

I notice my female harlequin doing this whenever she is cold her past mate did the same thing when it would get too warm. Used to be very concerned when they did this but now I just think they are being cute