Originally posted by _I_:

toggle pvp if you dont have one, just be sure to turn it off again when done murdering your tames

It's not possible to "murder" an animal, either in a game or in real life as it is a legal term.

Murder is the unlawful killing of another human without justification or valid excuse, especially the unlawful killing of another human with malice aforethought.

The proper term would be kill, not murder. Cull might be appropriate, but that is more commonly used for weak, sick or inferior animals, in this context.