all our stolen hens have been taken by foxes, even in broad daylight if they have wandered too far.
but we have lost a duck who was broody and with eggs though she never had a mark on her, neither was her body taken but her deadbody was in rigormortis in a "attack" position and half the eggs taken and the remaining were cold. im sure she died protecting her eggs.
we never knew what killed her but im sure it wasnt a fox. a neighbour said maybe a stoat or something like that, but thinking back maybe it was a bird of prey as her coop was open fronted and she was killed in daytime.