If you've ever made hard-boiled eggs for salads, sandwiches, and (of course) deviled eggs, you've likely cut into one and discovered that the outer yolk has turned slightly green. It has nothing to do with the egg itself—no need to blame the chicken here!—and everything to do with how you cooked the egg. Read on to learn more about what makes hard-boiled eggs go green, if these eggs are safe to eat, and how to boil eggs perfectly every time. Why Do Boiled Eggs Turn Green Around the Yolk?