Eggs are hard-shelled reproductive bodies of poultry. The shell is high in calcium carbonate, while the inner membrane, or egg white, is mostly protein. The egg's most inner section, called the yolk is a source of protein, fat, and many vitamins. Dried eggs are fully dehydrated eggs. They are made using spray drying in the same way that powdered milk is made. The major advantages of powdered eggs over fresh eggs are the price, reduced weight per volume of whole egg equivalent, and the shelf life.