I have done a lot of candling with my duck eggs and yes they are white but i am sure it is the same this when candling chicken eggs. At about 8 days you should see at least a dark spot in the yoke, with a vein or two. The dark chicken eggs I just figured out how to candle them and it works. Make the room completely black and take an LED flash light and a cardboard tube and hole the tube over the end of the flash light. Place the egg on the other end. In a completely black room or under a heavy blanket with no light you should see something in the eggs like veins. I didn't figure this out until my eggs were 17 days along. Mine are due on Monday and I can see some space in the egg other then the air cell but he has a couple more days to grow. They have to grow and develope fast since they are only incubated for a month before hatching. The ones you not sure just wait it out. I am giving mine until the 11th or 12th, and mine are due the 7th. So I am giving them another 5 days to hatch. I will say a prayer for your eggs. I know the waiting game is painful but be calm and wait or at least that is what I am being told, just don't help them out when they start to hatch. Let them get out on their own.
