Only today, at 23 years old, I learned that not every egg can hatch a …

Only today, at 23 years old, I learned that not every egg can hatch a chick I thought that if a hen sits on her eggs for three weeks, a chick will hatch ? Turns out there are fertilized and simple eggs? He told me this, then kissed me in the forehead and says "good thing you're still small, you're easy to surprise" ? Have you ever considered this?