The female has too sit on her eggs for a certain amount of time before the egg hatches??
So If you eat a egg with a duck that has that white dot it just means that the baby is starting to develop right??
Can you also take the egg out and check with a flashlight for that white dot?
1. Yes the hen would have to sit on the egg for 28 days for the egg to hatch.
2. No, the dot is the female gamete or the "egg" and when the ring forms around it that means its been fertilized by the male gamete or "sperm" so the chick hasn't started to develop yet its only the starting cell or "zygote" that would grow into a chick in the proper conditions.
3. No, it would be impossible to see through the eggshell, but once a hen has been fertilized and lays he first fertile egg, all the eggs for the next 2-4 weeks will be fertile as well.