These soy-free Duck eggs are bigger than chicken eggs. That means they have more of everything in them: more fat, more cholesterol, more protein, and more calories. They are also higher in Omega 3s and have an extremely long shelf life (6 weeks if you keep them refrigerated). Duck eggshells come in a much more varied array of colors. Imagine white, various shades of grey, light green, brown, speckled, to a nearly black egg, depending on the breed of the duck. But just like chicken eggs, the color of the shell has no relation to the flavor or other properties of the egg.