The duck hens are all laying, but in 3 inches of water!
So it looks like they actually don’t have any brooding instinct at all.
No little ducks.
Something got one of the eggs. It and another egg were strewn along the bank. Then I looked down into the water, and there were three eggs just sitting there.
One of the hens is a true wild mallard. One is a hybrid between a wild and a tame one (of a breed selected for egg production), and the other is a bloody mongrel.
The mallards spend next to no time on land. There are just too many predators.
So they are at a dead end.