Their mother is missing (I'm pretty sure she's dead) and they were hatching in my back yard, so I put them in a heated aquarium on a towel on my porch (with the door closed so my dog and cats don't kill them.) 10 have hatched so far with more eggs starting to hatch.
That's real cool you helped the ducklings. Is there like an animal shelter or vets which can help with the care of the ducks. Over here there's like the RSPCA who help with wildlife. I'd also try and keep an eye out for the mother duck if she does turn up but I think sadly your assumption about her is correct because she just wouldn't just leave her young.
Oh yeah, I can't keep ducks in my house like I'm Joey from Friends. Especially since I came out this morning and my cats and dog were sitting by the door dying to get in there to eat them.