An owl eating a bat is not cannibalism. If the talking owl were to eat another non-talking owl, that would be cannibalism. And that wouldn't happen, I don't think. Too many feathers and difficult to digest.
There's no instance of any of the talking animals eating one of their own kind. They eat the things that their kind should eat. The bears eat honey and fruits, and the panthers probably eat meat, but not from other panthers, etc...
I doubt that the kings of Cair Paravel served stewed mouse on their tables, and mice don't eat meat anyway, do they?
