If you hand turn your eggs, the developing embryo will look as though it is growing on one side- the side that faces up. When you turn your eggs the embryo will "resurface" to the top. It's a cool and educational experience and shows just why we turn our eggs. Once the embryo grows into a formed chick and has free willed movement it'll be bouncing around in there. If you're lucky you'll be able to make out a little foot when it's kicking around during candling. Such an awesome thing to see.