We can see when the egg is placed near an overhead projector that light passes through the transparent egg shell but we see a dark shadow where the network of veins are developing and the even darker still outline of the duck embryo.
We can keep an eye on the development by using this method which is non invasive. The following link has a gallery of images to show duck development visible through candling. Click here.
We will be able to observe any eggs that die during development and remove these from the incubator if required.
Hatching success rates in incubating duck eggs is rarely 100%, this is often due to fluctuating humidity (water) levels, not turned frequently enough or the duck not breaking through the membrane/shell if the membrane dries out. We can predict perhaps 6-8 of the 12 eggs to complete development and pip successfully.
One of our developing ducks can be seen in this photo
