Published January 1, 2013. From Cook's Illustrated.
Do duck eggs differ in flavor or texture from chicken eggs?
We purchased duck eggs ($4.49 per half-dozen) and eyeballed them next to large chicken eggs. In the carton, the eggs looked similar, but when we cracked open a few, we noticed that the yolks of the duck eggs were proportionally larger than those of the chicken eggs. In fact, when we separated the duck egg yolks from the whites and weighed each component, we found that the yolks contributed 42 percent of the total weight. When we ran the corresponding numbers for chicken eggs, we found that the yolks made up only 32 percent of the total weight.
Next, we made scrambled eggs and found more differences. The duck egg scramble was decidedly richer, with earthy, grassy flavors that weren’t present in the chicken eggs. These traits can probably be attributed to the facts that the birds have different diets and that duck eggs have a higher fat content than chicken eggs do.
But the scrambled duck eggs also had a dense, resilient texture that some tasters objected to. That’s because the duck egg whites contain more of the structure-building protein albumen than the whites of chicken eggs do. Because of this difference in composition, we don’t recommend swapping duck eggs for chicken eggs in recipes. But if you’re fond of yolks, duck eggs make a great breakfast.
Duck egg yolks (right) are proportionally larger than chicken egg yolks and have a different flavor. What's more, their whites are a different texture, so we don't recommend substituting.