You found 2 duck eggs in your friends pond a few days ago. They havent been incubated yet and you wonder if they are fertilized.Is there way to tell without waiting?

Candling is a technique that can be used to determine if a duck egg is fertilized. To candle an egg, you will need a bright flashlight and a dark room. Hold the egg in front of the flashlight in a dark room and shine the light through the egg. If the egg is fertile, you will see a dark spot, which is the embryo, inside the egg. If the egg is not fertilized, you will not see a dark spot.