A candling device is simply a pinpoint light source that is held behind the reptile egg. As the light passes through the shell, you see a shadow image on your side. If a reptile egg is infertile, it remains clear because there is no growth. Usually about a week after laying, the embryo of a fertile egg begins to grow, and you will first notice a small round disk. A week later, the disk will have grown, and more of the shell will become opaque, because the light cannot easily penetrate the tissues and blood vessels. After several weeks, the entire egg will appear opaque, because the body of the embryo and its many tissues simply stop all light.
Candlers are available from bird supply dealers, as chicken and parrot eggs often are candled on a regular basis. You also can try to make a simple candler by using a bright flashlight and shining it through a pair of pinholes in opposite ends of a small metal can (such as a tomato sauce can) lined with black paper. The holes concentrate the light so it penetrates the shell better. Be careful using homemade candlers, because the light may be hot enough to harm developing embryos. Don’t candle eggs every day — try about four or five days after they are laid and then at weekly intervals. Remember not to turn the eggs when you replace them in the incubator.
and alll you had to do was candle them..sigh.