Food coloring ducklings

Well I guess you are right I found this information on line

EGG Cam Chicks 2003

About Colored Chicks: Coloring embryos by injecting dye into eggs before they hatch has been practiced for years. By dyeing the chicks, we can identify the young of certain hatches or groups. Some scientists use this method to observe movements of wild birds (especially birds like ducks) after they leave the nests.

By coloring chicks, we can study how the chick’s feathers grow. The colored down (the fuzzy blue and green colors you see now) are replaced by juvenile feathers in about two weeks. You can see how the feathers change by watching the color pattern change on the baby chicks.

Dyeing by injection of the egg doesn’t affect the chick’s health, appetite, or growth. If you are considering dyeing chicks for a school project, please check with the animal health regulations in your community. This practice may or may not be allowed or be regulated.

Here is that link

http://lancaster.unl.edu/4h/Embryology/colorchickens.shtml