Weird cracking noise coming from ducks body

[birdsqueezer]

Kinda short to make an assessment....some visuals would help too.

My bad, they were in a shadowy area when I took the vid. As for visuals, they seem to move their feathers a lot more, exposing their downy feathers

 

[Crazy Maizie]

A better video showing the actual duck would definitely help. I'm not sure what you are referring to as far as the moving their feathers and exposing the downy feathers. That's kind of what ducks do.