Pocket Watch Visible Movement

How do I know if my chicken eggs will hatch?

I have 23 eggs fertilized about my own chickens I was held in a homemade incubator. I try to keep the constant temperature and humidity, but being homemade, it is sometimes difficult. Today the day is 21, which is the day when they should hatch. But nothing yet! I candled each and many different aspect. Some are all black, except for air pocket on top, and some have a large black spot in the air pockets visible (or something) around it. Others, who are clearly not fertile, are almost all clear. How do I know if the eggs hatch at all? I watched a YouTube video showing the movement of embryos in the egg, and I see no movement. Could it be because the shells of eggs are black and brown? I am so worried, help!

brown eggs are so difficult to plug I use to take the egg and put it in my ear very lightly tap I could here the baby peep chick. Give him a few more days. Good luck

The Nassau Antique Pocket Watch