If Jazz was abandoned, it is likely his mother knew he was "defective." This is the way of animals as doing so saves critical resources for offspring which have a chance of survival.
Many years ago I found a kitten in the middle of a highway. He was injured but a little surgery and he recovered fine. Given his condition, the vet speculated he had been abandoned by his mother. We also learned he had kidney problems and stayed near clinical dehydration. He lived a short seven years having succumbed to kidney failure.
Animal mamas know and they do not coddle their weak. Hunter did what a good dog does. It is amazing the connection humans and animals can have, and just as amazing the connection animals can have with each other.