Organic: Sometimes nothing.
Certified Organic, or USDA Organic: Cage-free, antibiotic-free, pesticide-free, with access to outdoors and fed only organic feed. The standards for organic eggs was raised just two days before President Obama left office in January, and it now requires a modicum of fresh air and sunlight within the barn. There is some tension between whether a consumer should prioritize pasture-raised or organic, as eggs aren’t necessarily both.
Brown: The shells of the eggs are from a type of hen that lays brown eggs, but there is no substantive difference in the edible material.* There are even chickens in South America that lay green eggs, just like in that book. I can’t speak to the health properties of green eggs, but brown- and white-shelled can be regarded as functionally identical. If someone is trying to make you think that brown eggs are healthier than white eggs (as is actually the case with brown rice versus white rice and whole grains versus refined grains), then this is a manipulative person.
Fertile: These eggs come from a hen that actually mated with a rooster. The USDA claims no nutritional benefit to fertile eggs.
Large: This is the average size for eggs.
Extra large: The average weight per dozen eggs is 27 ounces. This means that a carton of a dozen eggs could have one comically tiny egg and still be legally considered extra large. Or 11 small eggs and one enormous egg, as long as the average is at least 27 ounces. Then at a party, for example, you could say to a friend, “Look at this extra-large egg.” Your friend could say, “That looks like a small egg, to me.” And you could say, “Well, you’re wrong.” Conversation started. It’s that easy.
Jumbo: Even bigger.
Whoa: So big they might not be chicken eggs. But then what else would they be? This isn’t an actual label term, but I bet there’s a market for it.
Vegetarian-fed hens: There were no animal parts in the chicken feed, and, more tellingly, the hens did not spend time foraging in a pasture.
Omega-3: The birds ate at least a little bit of something that contains omega-3 fatty acids, which are generally considered to be a healthy nutrient when taken as part of a healthy lifestyle. But this feeding process isn’t guaranteed to manifest as higher levels of omega-3 in the eggs themselves. If you’re looking for omega-3 fatty acids, consider eating something other than eggs.
No GMOs: This label is increasingly common despite oblique relevance. Farmers have used selective breeding to make chickens that have enormous breasts—too large to even walk—and to grow quickly and to produce many eggs, some of them Jumbo. But none of this has been accomplished using “genetic modification” in the sense that people tend to object to when they say they’re avoiding “GMO.” That typically refers to organisms whose genes have been modified in a lab. That is the place where some people draw an ethical line. In any case, when you see GMO on a carton of eggs, it’s referring to the things the chickens were fed, meaning that no genes were added or removed from the elements of the feed that the chickens ate. There is no evidence to suggest that this would make for a better or healthier chicken egg.