Eggs in the Fridge Don't Hatch?

Most of the eggs that you buy at a grocery store probably haven't been fertilized by a rooster so there's no chick growing inside of it. When a hen lays a fertilized egg like I said she'll sit on it for about 21 days and during that time the chick inside of the egg is growing and is changing. It's kind of the same way that any animal grows inside of any mammal would grow inside of their mom but it just happens outside.