How did my baby puppies die and why are they cold

When mammals die, they get cold.
There are many reasons why newborn pups die.
Please tell us first - how old are you, and who was caring for the mother dog, and how is she now?

How did my baby puppies die and why are they cold
How old are you and how did this come to be ?

Puppies die for many reasons. A mother that's too young and can't properly care for them. A mother dog that doesn't have enough milk to give them the nourishment they need. A mother dog that dies leaving the babies without the proper care. Illness. Not having proper care from the owner, including a warm place to sleep, and medical issues that aren't dealt with, a vet check to make sure they're healthy.

Why do you have puppies? You're obviously not a breeder, so why do you have puppies?

As for being cold, once an animal dies, it gets cold, then it gets stiff when rigor mortis sets in. Then the animal will start to decay, the body will break down bit by bit. It's what happens when people die too.

How old are you? Why do you have puppies to care for to begin with?