If they're quite dead, then there's nothing inhumane about it. It seems a bit peculiar, granted, but as someone already said, maybe he's dismembering them to make sure that they don't "wake back up" later, seeing as it can be had to tell with cold blooded animals sometimes? Also, I was unclear: is he consuming them as well? I know a few people who have eaten deceased pets rather than "waste" the body, so maybe thats what he's up to.
There is a crazy cat hoarder down the street, and when her cats die, she chops them up and feeds them to her other cats. Someone called on it, but its technically not illegal since the cats were dead. I suppose if it keeps her cats from starving, then its ok, but she shouldn't have all those cats to begin with. Animal control in our area is pretty much useless.