What predator could this be?

[Humanbean68]

Found two ducks like this in my ‘outer’ pen, the daytime one that’s not covered. There’s no holes in the enclosure and no sign of anything digging under.
And night they are in a smaller covered run.

 

[nuthatched]

Oof. I'm sorry. Bones picked clean is usually bird of prey.

 

[Humanbean68]

That’s what I was thinking. I have a lot of ravens around.