"Slaughter" is a verb that means to kill animals for food, or to kill people violently in large numbers.
There are other collective nouns that are used to describe groups of animals, like:
* Flock: A group of birds
* Herd: A group of cattle, sheep, or other large mammals
* Pack: A group of wolves or dogs
* School: A group of fish
* Colony: A group of insects
* Pride: A group of lions
However, "slaughter" itself isn't a collective noun.