I think we need more information.
At least a couple of the bodies should have undergone a necropsy to determine the REAL cause of death(bleeding, suffocation, or broken necks). How were the goats kept(what type of fence/building). Were the adult goats in with the babies? How old were the babies? How big were the babies? Were they fainting goats? Over what time period did this happen?(1 night, a couple of nights, 2 days and a night, etc?).
I'm thinking it was a weasel or mink. Just because this sounds VERY similar to the weasel attacks on poultry. I could also see it being a dog. Unfortunately, I can also see it being a human predator.
It is scary what people are capable of and what people thrive on. I could see some sick person planning a stupid prank and wanting to stir up suspision in a small comunity/town.
It was definately NOT bats. Vampire bats suck the blood of living animals. They do not take enough to kill an animal like a goat, and definately not 20 of them. Vampires bats feed at night by sitting on the ground and making one(!) cut in an animal and by licking the blood and not 'sucking'.
Sorry to hear about the goats. It is a sad thing to think 20 goats were wasted, not even eaten. I hope they figure out and catch whatever did it.
-Kim