Master of Chaos!
It's kind of explained in the episode that bird pokemon eat rocks to digest food. (Most RL birds to this, even though it doesn't exactly work for owls.) That is your explanation for why Rowlet is going to be perfectly fine.I'm still weirded out Rowlet isn't dead for swallowing a damned rock. What, is his digestive system just going to...keep it in his stomach? That's not how biology works!