The NY Times recently published an article deciphering the claims on egg cartons. It grieves me (though it does not surprise me) that cage free and free range do not mean that the chickens were living in happy chicken utopias. Boing Boing had a nice summary:
Grade refers to firmness, AA best.
Emblems: National Organic Program, U.S.D.A., Animal Family Farmers (independents, less than 500 chickens), Humane Farm Animal Care, American Humane Society
Organic: needs National Organic Program emblem
Chickens are naturally omnivores, but non-vegetarian feed can contain all manner of terrible things
Pasture raised, which means non-vegetarian
Pasteurized, good for recipes with raw eggs
Antibiotics claim requires USDA or National Organic Program certification
Less than ideal, but better than meaningless:
Grade refers to firmness, A good.
Emblems: United Egg Producers Certified
Cage free almost meaningless, free range is a little better
Meaningless or bad:
Grade refers to firmness, B bad.
Terms natural, naturally raised, hormones are meaningless