How can I tell if a chicken egg is fertilized?

[Ariana Martinez]

My hen has been sitting on a nest of 9 eggs, and my rooster mates with her several times a day. So I was assuming they were fertilized. But just to be sure, I heard that a fertilized egg will float. So today I went out to the chicken coop with a bowl of water. I put an egg in and the egg sank to the bottom. I did the rest of the eggs and they all sank. Is there another way I can be sure that the eggs are fertilized?

 

[sourland]

Candle them. A developing egg will not float until the later part of the incubation period.