Never eaten duck eggs? Most people haven't. The differences between chicken and duck eggs, while slight, are noticeable by people who aren't used to the latter. Most of the people I know who have tried them prefer duck eggs, but not everyone likes them. In this primer I'll set out the differences between the two, but you really will just have to try them for yourself.
Fresh, free-range eggs
Very fresh eggs from free-range, healthy, well-fed chickens have deep orange yolks and a rich, complex flavor that few Americans have ever learned to associate with eggs. I had no idea what eggs were supposed to taste like until I was in my mid-20s, despite having grown up in the "Garden Spot of America."
I, like almost everyone else I know, was raised on supermarket eggs, sad pasty things laid by miserable overbred birds crammed into tiny wire cages and forced by hormones and underfeeding to overproduce eggs that are stored until what little flavor they once had is long gone: supermarket eggs may be months old by the time you eat them. This makes me sad, both for the chickens forced to lay the eggs and for the humans stuck eating them. It also makes me angry, furious actually, at the miserable humans who thought this sort of "agriculture" was ever a good idea.
And this, at bottom, is why Kathy and I raise ducks: the world needs more people doing this right, and the eggs are damn good. But enough preaching.
Very fresh, free-range duck eggs are similar to very fresh free-range chicken eggs, in both appearance and flavor. The yolks are deep orange; the flavor is rich; and fresh eggs "stand up" when cracked into a pan, because their structure hasn't had time to break down yet.
You will, however, notice more variation in appearance and flavor of free-range eggs, because the ducks or chickens haven't eaten as consistent a diet. When the grazing is good or we supplement the ducks' feed with extra greens, the yolks of their eggs are deeper orange; in winter weeks when they eat only their bagged feed, they are paler and yellow.
Nutrition and structure
Duck eggs have a slightly HIGHER FAT CONTENT and somewhat more cholesterol than chicken eggs. Unless you intend to survive exclusively on eggs, I don't see this as a nutritional problem. It may, in fact, be offset by the possible health benefits of free-range eggs: at least two studies have found that free-range eggs are significantly higher in omega-3 fatty acids than eggs from birds raised in confinement.
Duck eggs also have more ALBUMEN (the protein in the white) than chicken eggs, which gives them more structure when cooked. For this reason, many people prefer duck eggs for baking: the extra protein creates additional loft in cakes. Some pastry chefs warn against using duck eggs for this reason, but I have not found it to be a problem.
When fried, duck eggs set up firmer than chicken eggs (especially if they are very fresh). Many people call the result "rubbery" and recommend steam-frying them, but I think this is an exaggeration. I have actually grown to prefer the firm texture; the last time I had fried chicken eggs they felt a bit mushy.
The SHELLS of duck eggs are thicker than those of chicken eggs and just a bit rubbery, which makes them harder to crack. I was used to cracking eggs on the flat counter to prevent bits of shell getting into the egg, but I've gone back to using the edge of a bowl.
Appearance and flavor
Eggs from Khaki Campbells, are white, not brown. They look just like chicken eggs, except for the occasional mutant egg. (We once found one that was almost perfectly round; when we cracked it, we found it was all yolk. Very strange. But this happened only once, when the ducks had first started laying.)
Duck eggs come in a wide range of SIZES-as do chicken eggs, but you only get the one size from the store. At seven months old, our ducks lay eggs that average in size between large and extra large chicken eggs (large is the standard for supermarket eggs and in recipes). The sizes have grown steadily more consistent and somewhat larger since they began laying three months ago.
The FLAVOR of duck eggs is a little different from that of chicken eggs, but only a little. Very fresh, free-range chicken eggs, especially the yolks, have a faint flavor of chicken meat-a fact that shouldn't be surprising, since these eggs are designed to turn into chickens one day, but it was a bit of a surprise the first time I noticed it.
Duck eggs, logically enough, have a faint flavor of duck meat. Duck is rich and (if not cooked well) greasy, and I suspect that this, combined with the higher fat content, is why some people describe duck eggs as tasting oily. I don't find them oily at all, but they are rich, and their flavor is a bit darker than that of chicken eggs. That's the best I can describe it, other than to say that they are delicious. I think that they are superior to chicken eggs, although apparently not everyone agrees with me.
I don't generally worry about salmonella in fresh, properly stored eggs from healthy birds, but it can occur in duck eggs as well as chicken eggs. I have found conflicting research; it seems likely that ducks are less susceptible to salmonella than chickens, but that because the shells of duck eggs are more porous than those of chicken eggs, the eggs of an infected bird are more likely to be infected.
I am confident that our ducks are healthy and that our eggs have been stored properly, and so I simply don't worry about salmonella at home. Nevertheless, the usual caveats apply: very young children, the elderly, pregnant women, and anyone whose immune system has been compromised should cook eggs thoroughly to be safe. Simply treat duck eggs as you would chicken eggs. If you incline toward the "safe side," cook them thoroughly; if you think that the "food police" should stay the heck out of your kitchen, eat your eggs overeasy and don't worry about it.