List of parameters usable in slaughteranimal goals:

animalkey (Minecraft ID of an entity ('cow')):
The animal to be targeted.

bonusitem (item, chance and (optional) required tag ('leather,50' or 'boudin,50,oven')):
Extra item drop the villager can get.

aggressiveslaughter (boolean):
If true, the villager will slaughter animals until only half the reference amount (the number of spawn points) is left.


