Hen and duck eggs (Tobias / Alamy/ALAMY)

Before my sister and brother-in-law began avoiding animal products, their homestead in North Berwick, Maine, played host to 10 runner ducks. These birds’ job was to eat bugs in the garden, but after a hawk got two of them, the remaining eight had to be enclosed, making their usefulness questionable. Except for one not-so-little thing: They started laying eggs. I enjoyed them for a few weeks before the ducks were sold.

I’ve long been a fan of duck eggs, buying them from Pecan Meadow Farm at the 14th and U Farmers Market. I love their extra richness, the bigger yolk, the fact that when I hard-cook them, even all the way through, the yolk is creamy, never chalky. My favorite recipe: an omelet I made puffy by separating the whites from yolks and then beating up the whites before folding them back in.

Duck eggs are higher in fat, cholesterol and protein than chicken eggs. They add an unmistakable richness and a slightly heavier flavor to dishes. More differences:

● They’re usually significantly larger, although the size can vary. Most I’ve seen are equivalent to an extra-large or jumbo chicken egg. My rule: I substitute one-for-one in any recipe that calls for three eggs or fewer; any more than that, I use three duck eggs for every four chicken eggs.

● Their shells are thicker and harder. I usually crack chicken eggs on the counter to avoid sending small shell pieces into the eggs, but I use the side of a bowl or a sharp counter edge when cracking duck eggs.

■Because they have more protein, they cook up firmer and provide more lift to cakes and other baked goods.

■They’re usually more expensive. Daniel Shirk of Pecan Meadow Farm sells duck eggs for $6 a dozen, compared with $5 a dozen for chicken eggs.

Duck eggs are available at some area Whole Foods Markets and from farmers at these markets and others:

Pecan Meadow Farm, 14th and U Farmers Market, Saturdays 9 a.m.-1 p.m., starting May 5.

Twin Post Farm, Meridian Pint, 3400 11th St. NW, 11 a.m.-1 p.m. on April 28; Columbia Heights Community Marketplace, Saturdays 9 a.m.-1 p.m., starting May 12.

Grassential Farm, FreshFarm Market by the White House, 810 Vermont Ave. NW, starting May 3.

Waterview Foods, Dupont Circle FreshFarm Market, 20th Street NW between Massachusetts and Connecticut Avenues, Sundays, 8:30 to 1 p.m.

Many Rocks Farm Products, Silver Spring FreshFarm Market, Ellsworth Drive between Fenton Street and Georgia Avenue, Saturdays, 9 a.m. to 1 p.m.