Have you noticed a white spot on fresh egg yolks? That is a germinal disc. It is an indication if the egg is fertile or not.
A non-fertile germ spot will look solid white because it contains the female’s cells only. A fertile germ spot will have a somewhat clear center. A rooster must be present with the hens for an egg to be fertilized.
At egg farms where eggs are produced for human consumption, roosters are not present. Therefore the eggs you buy at grocery stores are non-fertile.
Source: https://bit.ly/2Kna9rA
