duck sitting on chicken eggs

[Birdmania]

Duck is sitting on hen eggs. any concerns I should be aware of? She was a great momma to 5 ducklings last year but all my male ducks got taken by predators last fall. She has decided to sit on some chicken eggs and refuses to move off of them.
Will she hatch them and raise them as her own?

 

[The Moonshiner]

Yes she will.
The biggest issue is that once they hatch she will eventually take them into any available water and they will drown or die from being chilled.
If they do survive without any water mishaps they will grow to have identity issues.
Once grown mine never left the duck flock and never interacted much with the chickens.

 

[Birdmania]

My ducks and chickens all flock together as well as the geese. So I don.t think that will be a problem.

 

[The Moonshiner]

Mine do to for the most part. The ducks sleep out in the open while the chickens go to roost. Mine would never enter a structure or roost off of the ground. They just plopped down with the ducks at night. Also when it rained they would stay out and play like the ducks until they got soaked to the bone then they would go stand against a tree or some sort of at least wind break.
It really wasn't a great life for them.
Now when I do it I take the chicks away when they hatch.
Oddly enough the opposite also works but with different results. A hen of course won't take ducklings into water but their instinct will and she can't stop them. It's entertaining for a minute when they would run into a puddle and the hen would panic and run circles around the puddle trying to call them out of it.
When the ducklings grew up they always stayed somewhat attached to the hen or at least never forgot her but they would move on to hang with the ducks and never try to be chickens.