How can you tell when a Khaki Campbell duck is going broody?

[Darklingstorm]

I have a Khaki Campbell duck that has been burying her egg in the pine shaving everyday for the last week. Yesterday she got out but still laid her egg in the nest box, I put her back inside the pen and she stayed there all day. Today she was out again but no egg. Several hours later I go to check my chickens and there is an egg outside the pen and I'm 100% sure it was not there earlier since it was the area I trapped her in to catch her. She was still or back in the pen when I found the egg. They have plenty of water, refresh it daily and plenty of food. I also give treats out daily. When she gets out she doesn't go anywhere, just hangs out around the fence to her pen. I also have a drake and he hasn't gotten out.

Is she going broody? Should I leave the eggs in the nest and see if she will sit (I do want another female out there, love the eggs)?

 

[learycow]

It might be too late in the year for her to sit on eggs. My khakis were all broody this year, but stopped sitting on their eggs in August. They still lay everyday, cover their eggs in the hay, but none were sitting so I started to collect the eggs daily.
I wouldn't let the eggs sit for more than a week. If they are going to go broody, they usually do it after laying 4-5 eggs. If you have some in the nest that are older than a week, chances are they are no longer good. You might just have to wait until spring.