Duck sphincter seems to exist!

[RebinNH]

I was under the impression that ducks do not have a sphincter but now that my two muscovy hens have built a beautiful share nest they keep it totally clean. No poop or pee. They are in the coop for over 12 hours at night and do not poop at all! They must have control to do this or perhaps it is something hormonal...?

 

[Canadian Wind]

I was under the impression that ducks do not have a sphincter but now that my two muscovy hens have built a beautiful share nest they keep it totally clean. No poop or pee. They are in the coop for over 12 hours at night and do not poop at all! They must have control to do this or perhaps it is something hormonal...?

Most broody birds don't poop their nests, and are able to 'hold it' until they go out or can scoot to the edge and let fly.

 

[RebinNH]

Yes, so then I guess it is hormonal control.