Have you ever cracked an egg and the yolk was bloody? What is that from?!
Answers: It was fertilized, and the embryo had begun to develop.
It means it was fertilized.
It means that there was a chick embryo in it.
It has been fertilized.
Yes. It means the egg was fertilized.
I, personally, never use those eggs. That's one reason why when you are making something, you crack the egg into a bowl before adding to to the rest of the ingredients.