fail incubation, whats going wrong?

[muus]

Hi
Mi mallard hen started laying eggs at february and day 1 of this month started incubating.....ONLY AT NIGHT!!! so I don't understand why. Now the eggs are in the incubator and I let some white chiken eggs for her to incubate them and then take care of her own ducklings.
What do you think about this mother?
Thanks

 

[Amiga]

I have read here that sometimes they don't sit all day till there are enough eggs - in her opinion. Also I have Runners who only get semi-broody.

 

[muus]

I have read here that sometimes they don't sit all day till there are enough eggs - in her opinion.  Also I have Runners who only get semi-broody.

That is true, she wanted to have 12 eggs like her mother so now she started incubating them.
Thanks