I just bought a giant leopard and a giant tiger from those tree-loving elves. I also bought an elephant, which I promptly slaughtered for a strange mood dwarf. But said dwarf has yet to be placated! I have decided to slay the leopard to placate the poor fool.
Yet, said leopard does not show up on my stocks screen! Why is this? Is there another way to butcher the animal?
While JavadocMD's comment/answer may work. (Assuming you can have them kill it, if not you could still throw it in a deep pit.) This would usually result in mutilating the corpse, or maybe your dwarves would bury it.
The easiest and probably best way would be to train it as a war/hunting animal at the kennel. Then it will show up in the animal list and can be butchered.
As for why it won't normally show up, it's probably a bug related to the fact that you bought it.
As soon as the elf diplomat left, the missing animals appeared on the z-stocks screen.
