Intelligence voters: pigs vs. babies?
Suffering voters: okay to kill people who've wireheaded?
Human DNA voters: what about the inevitable future when human DNA starts getting modified?
Value to human voters: I don't know the question for this but I'm open to suggestions
How much _individual rights_ it has. Humans have rights (unless they forfeit them by being criminals, killing in self-defense is OK & hanging Hitler would be perfectly fine).
Rights do not apply to animals because they have no capacity to reason.
Very small children also have no capacity to reason. There's also some levels of mental disability which keeps humans at lower levels of function than many animals.