Broody Duck!

[toastyteddy]

Recently, I haven't noticed my mallard/Pekin duck out in the yard, even when changing her pool.
I went looking for her and found she has made a massive nest in one of the laying boxes. She seems to be sitting on quite a few eggs, but she has done this before a few years ago (the last batch was infertile). She is about 6 - 7 years old and has only been broody twice.
I have no males, but I have had to fend off some wild male mallards from my pen in the years.

Is there a way to check if her eggs are fertile? She's not leaving her nest to eat or drink, so I would like to know if I can start pulling her off of the nest.

 

[sourland]

You can candle the eggs to determine whether or not they are developing.

 

[SilverBirds]

If you don't have any males they aren't fertile (unless a wild duck came across her). Candle the eggs to see if you can spot development. If they are clear I'd chuck them.