I night have noticed that after the butcher task will immediately be set. Now, if you rightclick on the dead animal, you can order your selected hunters to start butcher it right away – if they have butchering tools like biface or any other type of knife in their inventory. The butcher icon will turn green, if even one has one.
What type of tool your manual selected hunters have equipped is random. Because how the game works, you can’t assign them manually what type of tool they have.
BUT: If you order them to pick up the desired tool they will have them in their inventory (and took up a slot), but they can use them from there. This is admittedly extreme mircomanaging, but reasonable for early game play. Or desperated times.
AND: After you assigned your hunters a target, everyone without a hunting weapon (if you haven’t hold the key “H” during selection, for example) will fetch one. This means of course, some parts of your hunting party will have to run back and forth to catch up.
Basically the same applies for the butchering part. If you assigned your hunting party to butcher, the ones without knifes will go fetch one – if the AI-director is working correctly.
And yes, all that means that there can be more than one butchering an animal. But having to manually pick up tools means that there will be less space for transporting the prey back to the settlement.
Setting work areas for hunting and increasing the maximum amount of workers resolves in multiple hunted animals, with one hunter after them each (haven’t seen any other behaviour myself. Please correct me if I’m wrong).
Butchering killed game will be a lot easier after unlocking the sledge. Then the AI-director will assign such work (and hauling in general) a lot better (for now).