Dove has two eggs, which one is fertile?

I have one male and one female dove. Two eggs were laid. She's been sitting on them for about 18 days now, one had turned a pinkish color the other is white. Which one is probably fertile and going to hatch, if any.
Answers:
You can "candle" eggs to see if the chick is developing inside. To do this, hold the egg over a flashlight and cup your hand around the egg making a sort of tunnel to block out light (except for the flashlight.) With a fertile egg, you should see a dark shadow (the embryo) with veins in the yolk. Or, if it is near hatching, most of the inside will be dark. With a non-fertile egg, the light will be evenly diffused -- hatcheries call this a "clear" egg. It is not fertile.