One time I was going around and collecting up the eggs from our free range chickens when I lived in Texas, one slipped out of my hand and hit the dirt. It cracked open, and a chicken ran right up to it and began eating the contents! I was shocked to say the least! Then years later, on TV I saw a program about learned behavior in animals, and on some island or other, these small black birds learned that if they roll the eggs of other birds out of the nest and bang them against a rock, they can get an easy meal.