I can't seem to properly register on the bugtracker, so i'm posting this here:
Burial of fortress pets is known to have two notable bugs:
- cats who adopted a dwarf never or only rarely get buried (but in my experience, dwarfs tend to not care about their corpses rotting; might be sufficiently isolated refuse piles, though)
- dead work animals assigned to a dwarf typically don't get buried at all and the dwarf does get a bad feeling for seeing their unburied corpse/skeleton.
When trying to start a pet cavy breeding programme in another fort i noticed that all my dead cavies suddenly got buried - not one had gotten adopted, they had merely been set to 'available'. Intrigued by this, i set some dogs to 'available' immediately before training them for war. I did not assign those dogs to dwarfs, which might mess things up again, but the unassigned war dogs (and the one who got adopted before getting trained...) were all buried after death.
So it appears that what determines whether a tame animal gets buried or not is only whether or not the 'available' flag has been set.
Unfortunately i don't have a usable testing fort around to check whether this knowledge can be used to get individually assigned war and hunting dogs buried after all, but it would certainly be worth a try.