Additionally, animals thought to be vegetarians, such as cows, rabbits, and turtles, will, when the opportunity arises, eat meat. Dairy cows will even stomp barn mice, rabbits, and chickens then eat them.
http://scienceblogs.com/tetrapodzoology/2010/12/20/carnivory-in-cows-and-deer/
Deer will eat baby quail.