Inside an egg, you'll get 70 calories, 4.5 grams of fat, 6 grams of protein and 13 vitamins and minerals in the yolk alone.
Free-range means chickens producing eggs have at least some access to the outside. It could be a few inches or an acre. The term is not government-regulated, so it is up to the farmer's discretion.
Cage-free does not mean free-range, but rather hens have some room to roam. It could be a barn or warehouse, but they have some area to walk and spread their wings. Once again, it's not government-regulated.
The government's definition of "natural" is no artificial flavors or colors, which might have you wondering about brown eggs. While there is no difference in the nutrient value, brown eggs actually get their pigment from brown hens.
Vegetarian-fed eggs means that the hens are fed a diet that is free of animal products, which is something chickens prefer.
If you see a carton stating eggs with omega-3, that means the hens are eating a diet high in these fats, most likely flax and supplemented algae that raises the omega-3 content of the egg.
But check how much DHA you are getting in accordance to the Recommended Daily Allowance to make sure you are getting your money's worth, as they often cost a bit more.
When you see a letter grade on your egg, you should know that this is a voluntary inspection that some farms use. About a third of eggs in the market are inspected by USDA certifiers.
Grade AA has thick, firm whites and high, round yolks, while grade A has reasonably firm whites and high, round yolks. Yet both work equally well in cooking applications.
The most important term you'll see is: organic. That term certifies that the hen has not had any growth hormones or antibiotics nor has it eaten any feed that's been sprayed with pesticides for at least three years or more.
We checked prices and found that a regular dozen large eggs cost about $2 and change, but a dozen eggs that were either fortified with omega-3 or were organic cost more than $4 a dozen.