Just started my search on wiki and this sentence is quite interesting: "By the end of the Copper Age in 3000 BCE, animal sacrifice had become a common practice across many cultures, and appeared to have become more generally restricted to domestic livestock." I feel we're often hearing sacrifices were on deer, goats etc but wiki seems to say that Egyptian sacrifices were later restricted to animals like sheep, cows, swine, geese.

Also: "All or only part of a sacrificial animal may be offered; some cultures, like the ancient and modern Greeks, eat most of the edible parts of the sacrifice in a feast, and burnt the rest as an offering. Others burnt the whole animal offering, called a holocaust. Usually, the best animal or best share of the animal is the one presented for offering."

Definition of "A Holocaust" on wiki - A holocaust is a religious animal sacrifice that is completely consumed by fire. The word derives from the Ancient Greek holokaustos which is used solely for one of the major forms of sacrifice, also known as a burnt offering. Wow! Thinking of gas chambers.. Thats also what they use on pigs to knock them unconscious! Here's the link to wiki if you want a read, I haven't read it all yet but will do more digging! https://en.m.wikipedia.org/wiki/Animal_sacrifice