How do you tell if an egg is fertile or not? My ducks are very young (a male and female at 1 month, 2 more females born this morning!) so we won't really need to worry about this for a while, but this is something I need to know. We know we don't want to keep the ducklings they have but would like to eat or sell the unfertile duck eggs. How do we tell the difference so we don't accidentally sell or eat one with a baby inside? Since we have a male will they all be fertile? Also is there anywhere I can sell any ducklings they have?