Found this terrific post on Tim Ferriss' website (via the Farm to Table blog), discussing meat labeling. Ferriss referenced the article It’s a Jungle Out There, by Marissa Guggiana in Meatpaper, which I'll quote here as well:
Some of the claims [on meat packaging labels] are backed by USDA authority and have concrete definitions, dutifully recorded in the federal register; some are monitored by animal-interest or environmental groups; some are created by businesses themselves, which employ private auditors to guarantee compliance with their criteria.
ALL NATURAL This means meat that is minimally processed with no artificial or synthetic products. It is not regulated, however, so anyone can put it on their package. This claim has no clout.
FREE RANGE This means strictly that the animal has some access to outdoors. There is no regulation for use of this term, except in the case of chickens raised for consumption. “Pasture-raised” is a more meaningful term concerning the animal’s welfare.
ORGANIC USDA and third-party certified. This certification means that livestock wasn’t treated with hormones or antibiotics and was fed a pesticide-free diet. Read the whole posting here.