What chicken and duck predator can squeeze through 2x4" wire mesh fence?

[kaumlauf]

Hello fellow fowl folks,
For the last few nights, something has been getting at our ducks and chickens. We have a 4' electrified fence. But, the main fence is a heavy gauge wire mesh of 2"x4" openings. When it takes a bird, it eats the main body but leaves the head and neck, innards and wings. Sometimes there are a few loose feathers, sometimes not. One duck is limping, and has some feather loss on the leg.
Are we doomed?

 

[LoveThemBirds]

Snakes,or weasels.....

 

[Folly's place]

Add hardware cloth to the wire mesh ASAP, and set live traps o catch and dispatch your current predator. Bring you birds in to safety before they are all gone! Mary

 

[eviemethugh]

Hmm do you have a roof? I wouldn't think so with electric fence but thought I would ask. My first thought is that your fence sounds like the perfect thing for a small animal (with apparently discerning tastes to not eat the innards!) is climbing your fence.
Edited to add: I mean the "main" part of the fence sounds climb-able if there is a way/area without electricity.

 

[CrazyTalk]

Snakes,or weasels.....

The description of the conditions of the birds pretty much eliminates these two.

I agree with @eviemethugh - is there a roof here? Maybe owls? Racoons also love to eat birds through fencing.