Mice can be problems. I say yay!
I recall one of my earliest chickens catching a small snake and running all over the garden with it when the other chickens chased her. She did not have time to kill it and instead swallowed it down. Walked around a little funny for a while (wings partly out).
Our Quirky Companions!
The small snakes we get around here aren't much bigger than the large nightcrawler. Most of them are earth snakes. It wouldn't be difficult for the chickens and ducks to swallow them whole. There's also no shortage of them either.