I feel like this isn't the first time the Witch has needed to get a new familar, even if she didn't kill them herself. She probably doesn't live the safest of lifestyles, and a few do-gooders probably know to attack a witch's familiar, no matter how cute.
But yes, it does look a wee bit smaller, but that could just be the art style. Unless you are referring THAT comic, and I have completely missed the joke again.