Every egg yolk has a white disc called a blastoderm. It is usually visible but may be very pale. In an infertile egg, the blastoderm is solid white. In a fertile egg, the disc has a faint or distinct ring that makes it look like a donut or bulls-eye. Fertile eggs are completely edible. In fact, some people consider fertile eggs more nutritious than infertile eggs, but scientific research does not confirm this. Fresh fertile eggs collected daily will not have embryos in them. Embryos do not begin to develop unless the eggs are in a favorable warm environment under a broody hen or in an artificial incubator.
