How can i tell if my pigeon eggs are fertile ?

I have 6 breeding pair with 2 eggs a piece. What are the chances of all the eggs being fertile and me getting 12 baby pigeons in the next 17 days. Ive seen them all mating.What is the odds of them being fertile ? And are most of them fertile or not in a group of eggs ?

Probably pretty good chance they are all fertile if the parent birds have been seen mating. I suppose you could candle the eggs at around 8 days if you wanted to, go into a very dark room and shine a bright torch behind the egg, if its fertile you will see a network of veins developing. If the light shines right through it probably isn't fertile. Trouble is this can disturb the birds. Its up to you, might be easier to let nature take its course and see what hatches out.

Candle them.Take them from the parents at night when they can't beat you up and hold them over a flashlight. If you see clear all around and them a dark ball then it is fertile. It will literally look like a baby in there. It it is all black or no black at all it is rotten or there is no baby.