and then lost it, take on baby ducklings as their own? I was thinking of buying a few newly hatched ducklings if she would.
Will a mama duck who only had one duckling hatch
Possibly. Is your duck still sitting or has she abandoned the nest?
If she is still sitting then I would try putting a couple of ducklings under her at night (make sure it is dark and that she is sitting on the nest). Protect them with the back of your hand so she doesn't bite at them by accident (she might try to bite your hand). Be prepared for her to not be interested and have a brooder all set up just in case.
If she is not sitting any more then I'd say that she would not be interested in mothering any more ducklings. Maybe wait till she is broody again.
Sorry that you didn't end up with any ducklings from your hatch. It's always a bit sad, after the anticipation during the incubation period.
That's a shame about the duckling.... They can jump quite well and can easily get into waterers that seem too high. With a mother duck, it's probably best to provide only a shallow waterer and then once a day provide a deeper one (like a small bucket) that she can throughly wash her face and bill in.
I'm sure your duck will go broody again though and you will be able to try again with fertile eggs (or day old ducklings). Best of luck for your next hatch