What it means: This means that the finished product hasn't undergone certain unnatural processes; in this case, that product is the egg.
Can you trust it? No! Neither the FDA nor the USDA have set any definitions for the word "natural" when it comes to eggs, and it's highly misleading. "Natural" eggs may have come from hens pumped up with antibiotics, fed feed containing arsenic or genetically modified corn or soy. And it certainly doesn't mean the chickens were raised in clean, humane conditions.
What it means: Pastured chickens are often housed on grassland in portable shelters that are periodically moved to give the chickens fresh pasture (and bugs!). Studies have shown chickens raised on pasture have twice the amount of vitamin E and more than 2.5 times more omega-3 fatty acid levels.
Can you trust it? Only if you're buying from a farmer you know. There's no third-party inspection required to ensure that hens are roaming around a grassy pasture, but if you're buying eggs from a local farmer, you can ask him or her—or even see for yourself—how the animals are raised, what they're eating and whether they've been treated with antibiotics.
Read more: The Best Backyard Chickens
What it means: Hens were fed feed with an increased amount of omega-3s, which may have come from flaxseeds, fish oil or algae. Technically, caged hens could also be fed flax feed, so don't equate this label with better living standards.
Can you trust it? Sort of. You can always compare omega-3 claims with the Nutrition Info panel on the carton. Factory-farmed eggs naturally have about 50 milligrams and many "omega-3 enriched" eggs often have that same amount. So you're paying twice the price for regular eggs. Furthermore, there's no guarantee you're getting the beneficial EPA and DHA oils found in fish and algae. You could be getting ALA omega 3s from flaxseed, which are still healthy but not as beneficial. Finally, keep in mind that pastured eggs have twice the amount of beneficial omega-3s as factory-farmed eggs anyway, and the hens get to be outside.
What it means: The birds are cage-free and continuous outdoor access is required. They must be able to perform natural behaviors like nesting, perching, and dust bathing, and birds must be allowed to molt naturally. Beak cutting is also prohibited. Antibiotic use is allowed, but any animal that receives them has to be removed from egg-laying operations for an "antibiotic withdrawal" period. And though organic food isn't required, the program prohibits the use of animal byproducts, and encourages GMO-free food whenever possible.
Can you trust it? Absolutely. A certification program of the independent, nonprofit Animal Welfare Institute, the Humane Society dubs this the highest animal welfare standard of any third-party auditing program. Farmers are subject to annual audits to ensure all standards are being met.
Read more: The 7 Best Eggs You're Not Eating
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