I bought my duck eggs from a fellow vendor at the Austin Urban Farmers Market. I hadn't purchased eggs since we got our chickens last July, so it was an odd sensation, but worth the money. The yolks from his ducks weren't as orange as my chickens, despite the fact that they seemed to be grazing. That may simply be due to our drought and the lack of green forage this time of year.
Duck eggs differ from chicken eggs in a few ways. Duck eggs have a higher fat content and also contain more albumen (the protein in the white). This higher fat and more albumen give duck eggs more structure which creates greater loft when baking. For this reason many bakers choose to use duck eggs for their breads, etc. I really saw the difference in my loaves and plan on using duck eggs whenever possible when i start experimenting with bread again ( I need to take a month or two off, i've gained 3 pounds already and don't want to give up Christmas cookies just yet!). Duck eggshells are a bit more rubbery and harder to crack than chicken eggs as well. I haven't cooked and eaten one, but have read that duck eggs taste similar to chicken eggs, but perhaps more 'ducky' ( duck meat is darker than chicken meat ) with a tendency to cook up a bit rubbery.
For a complete nutritional analysis, check out this great website, duck eggs dot com. I love our chickens and wouldn't live without them, but i'm excited to have a bit more land to add some more poultry to. We had been planning on getting a set of geese to act as sentinels and patrol the front yard for snails. I think we will also or instead have to get some ducks as well. Ducks are great (not as good as guineas) in the garden because they go for the bugs and snails first. You can leave ducks in your garden for about 10 minutes before they start going for your crops. Chickens, on the other hand, will kick up and peck out every bit of green they can get their hands on.
Curious about duck eggs? Visit our farmers market in January and get a dozen from Munkebo Farms or Purple Goose Ranch. Our market will be open again starting January 8th 2011 10 - 3 at 5109 Manchaca Road.