The yolk of duck eggs is formed on the ovary, and the protein is formed in the swollen part of fallopian tube. Their growth and maturity require the regulation of hormones and the supply of various nutrients in the blood, including pigments. The color changes of yolk, protein and eggshell of healthy laying ducks vary with varieties, feed and light.
Different feeds will lead to the color changes of duck egg yolk and protein. This change has little effect on food safety and nutritional value. In addition, if sick laying ducks are infected with sarcomatosis and Newcastle disease, the above changes will also occur. But this kind of duck basically does not lay eggs during the onset period.
According to experience, there are two possible ways for egg white to turn green. One is that the place where the eggs are stored is not clean, and after a long time, dirty things penetrate into the eggs, causing the eggs to deteriorate; Another possibility is that some pigments are added to duck feed, which leads to the discoloration of egg white. It is best not to eat such eggs. But it should be no problem. Just pay attention next time.