The short version: Free range eggs are less likely to have salmonella than battery-laid eggs at the grocery, not as much junk (antibiotics, hormones, steroids) in them either, and nutritional differences are rather significant. See excerpt below:
Nutrient Differences in Conventional Eggs Compared to Free Range EggsThe comparison between conventional battery-raised eggs and free ranges eggs is stunning. Mother Earth News had free ranges eggs tested to see what their nutrient levels are and compared the results to the official USDA data for commercial eggs.The results varied from farm to farm, but the average free range egg results showed:
- 1⁄3 less cholesterol
- 1⁄4 less saturated fat
- 2⁄3 more vitamin A
- 3 times more vitamin E
- 7 times more beta carotene
- 21 times more omega-3 fatty acidKeep in mind that these eggs were from hens that Mother Earth News considers legitimately free range. They spend all or most of their lives outdoors, roosting in trees if they choose. This is not what is usually meant by free range eggs in supermarkets. Usually, those eggs are from chickens that can hardly be distinguished from battery-raised ones. The requirements for the free range label are laughable, with only limited access to the outdoors—and that does not mean pasture—and often nearly as crowded as those labeled battery-raised. As often as not, the outdoors that supermarket "free range" birds see has no grass, but only concrete under their feet, and no real space to roam.