I've currently got a duck sitting on eggs.

A couple of days ago my wife found 1 egg outside the nest,

an approx 1 inch hole in the side & the insides gone.

I've seen a couple before like this,

but Im surprised its happened while she's broody,

as she attacks me if I stick my hand in the nest.

Must be something fairly big & aggressive Im thinking.

Anyone got any suggestions for the culprit ?

Monitor lizards are sneaky and rarely seen. If you live in an area that has them, they could easily be the problem. Don't rule out rats either.

I think if it was a monitor it would swallow egg whole or carry it off.

Also would probably take all the eggs.

Maybe rat, I didnt take a close enough look to check for teeth marks.

snakes would also love to punch a tiny hole and sucked out all the juicy contents as well.

but 1 inch hole is a little too large for snake endeavor though.

Having seen some of our ducks eating newly hatched chicks of others, I wouldn't be surprised if the contents of your egg were eaten by another duck.

Thats a possibility, we've got 2 ducks.

But I would have thought the broody one would fight it off.

Recently the wife has beign losing eggs like you describe only to find out at night time that we seem to be farming rats too,some poison laid down for them inside 1.5inch pipe prob solved

not your girlfriend hehehehehe