1st: Should this pup have been abandoned in a park? Of course not.
2nd: Multiple birth defects in a pure bred dog does suggest this may be a pup from a breeder that may not be reputable.
3rd: If it WAS just a family that ENDED up with pups, maybe we can assume the others were healthy and adopted out, but they didn't know what to do with this one.
4th: Have you seen Vet prices lately? This is the kind of thing that quite possibly would have ended with a family that goes DEEP in to debt, or she would have been euthanized.
They clearly put this good girl where she would be found and had a CHANCE something like this would happen.