[Jamestown1630]

I wonder if she took on another brood when something happened to their mother.

[skr]

It’s more likely that the ducklings adopted her. She doesn’t have to feed them, so there’s no great urgency to chase the extras off.

[Eric in the Ozarks]

Sometimes, a mom duck doesn’t want to nest-sit her eggs so she deposits them in the nest of a more mature duck. We’ve observed this several times in early spring...

[Vigilanteman]

More than likely. When I was a pup, we raised chickens. In general, the Asiatic breeds (Cochins, Brahamas) made great mothers. The lighter egg laying breeds like Leghorns did not.

We had a side business of renting out or (for the right price) selling hens to people who wanted to raise chicks the old fashioned way. One of our Brahama hens (she was a keeper) acquired 22 chicks one summer. Only 9 were her own. The others came from failed mama hens. Just like people, some of them are just too lazy, too stupid or whatever to care for their own.

[shotgun]

We have a hen Turkey that chased a chicken off her nest and hatched out the 12 chicken chicks. 2 days later another one of yard hens went missing which left her 12 chicks orphaned. We placed them with Henny and she raised all 24. Problem with turkeys is they don’t scratch and peck so the chicks has figure that out. But Henny was quite the protector and always stood over them.