A fertile egg will have clear signs of development such as networks of blood vessels present, an opaque shape of an embryo at the larger end of the egg, and even movement within the egg. A fertile egg with an embryo that has stopped developing will have a blood ring or blood streaks observable in the egg. Since the embryo is no longer viable, the blood vessels that once supported it have pulled away from it. An infertile egg or yolker will look fairly clear, with no blood streaks, rings, or vessels.
A fertile egg will have clear signs of development such as networks of blood vessels present, an opaque shape of an embryo at the larger end of the egg, and even movement within the egg. A fertile egg with an embryo that has stopped developing will have a blood ring or blood streaks observable in the egg. Since the embryo is no longer viable, the blood vessels that once supported it have pulled away from it. An infertile egg or yolker will look fairly clear, with no blood streaks, rings, or vessels.
Wait until your bird eggs are a few days old and all possible embryos have developed. In practice, it is best to only move possibly fertile eggs every once in a while and never too often. Taking an egg from its incubator too early can stunt development and taking an egg too late in its development can hurt the chick inside. Get a bowl of warm water. Be sure to use warm water in case your bird egg is fertile. Carefully place the eggs in the water. Be gentle, as some eggs are very fragile. Observe if your eggs float or sink. Return your fertile eggs back to the incubator as soon as possible.
Fertile eggs will have a blastoderm that looks like a white bullseye or circle. The white colour of the blastoderm will be quite opaque and its edges solid and pronounced. A lighter, almost transparent, outer later will surround the denser spot. Infertile eggs will have a blastodisc that will have an irregular shape and its white colour is very faint and foggy. All eggs will have a white spot or blastodisc whether or not it is fertile.
An unfertilized egg or an egg only containing female genetic material is called a blastodisc. In fertile eggs or eggs that contain both female and male genetic material, the blastodisc is then term a blastoderm. The blastoderm is also called the first stage of embryonic development.
This method is not recommended for consumption if you are checking chicken eggs. If your egg has been in an incubator for 21 days or left out in room temperature for more than 7 to 10 days, the egg will have most likely gone bad or is beginning to rot.
