Why can't I butcher dead chinchillas?

So my hunterdwarf has been out in the field, and he's killed and hauled back some chinchilla corpses to my butcher shop. The only problem is that when the corpses are placed in the butcher shop neither does it trigger an automatic butcher animal job, nor will it let me manually assign the job. If I manually assign it'll just give the announcement:

Blah blah, Farmer cancels butcher an animal: Needs butcherable nearby unrotten item.

As far as I can tell from the wiki etc. any animal that my hunters kill should be butcherable, so I have no idea why it wont let my dwarfs feast on delicious small furry animals.

Screenshot of butcher shop:

Chincillas are small.

So small, in fact, that butchering them will yield no meat at all.

The Dwarven Butcher realizes this, and decides that butchering the corpse for no meat isn't worth the effort, and simply ignores it.

Essentially, your dwarves are lazy, but in this case, they're actually being productively lazy instead of uselessly lazy (wasting time butchering things for no return).