I have five cats. The Bad Cats -- so named because they tear up everything, knock over everything and potty thisclose to the litter boxes but still on the floor -- have FINALLY learned to kill the mice that sneak into the basement of the farmhouse. Of course, they leave at least half a mouse so I know they were working.
The fifth cat, Mr. Magoo, was born in my back yard when I lived in town. He was born eyeless and his mom didn't seem to concerned with keeping him alive. He lives upstairs in the farmhouse because he KNOWS to potty inside the box and, because he's blind, he's not trying to jump up on shelves or counters. Goo, as he is known, co-exists with an obnoxiously playful rescue terrier and a house chicken.