We've just come back from a holiday on a quiet Greek island. One morning we watched a ginger and white cat trotting purposefully across the field where the hens were, and then through the hole into the henhouse. There followed a bit of a kerfuffle, and we feared the worst - then out came the cat with a gigantic rat clenched firmly between his jaws.

Mind, I don't think I'd advocate introducing a cat to your hen run ;-)