Brown duck egg yolks
My ducks forage in the yard and a small patch of woods along our driveway. I've recently had a few duck eggs with brown yolks. From what I can find online, it looks like the coloring is caused by the ducks eating acorns; the tannins turn the yolks green or brown. I'm hoping to find someone who can confirm that the eggs with brown yolks are safe for human consumption and possibly an article that will explain why this happens in more detail. Thanks!
Allegany County Maryland poultry
The color of egg yolks depends on the bird's diet. A free-range duck or chicken with access to feed that is rich in brown pigments (such as tannins that are found in most nuts) will lay eggs with brown-colored yolks while those that eat corn (which is rich in xanthophyll) will lay eggs with yellow-colored yolks. The eggs should be safe to eat.