Day 10 Incubated Chicken eggs help.

So tomorrow will be day 10 for my incubated amberlink eggs. When i candled them all i saw was dark and could vaguely make out veins and a black dot pulsating back and forth. How do i know if these eggs are still viable? Does movement in the egg verify this? I dont know if the movement in the egg is from me rotating it or if its from the moving embryo. Again, the egg looked very dark and i could barely make out anything. Any information would be great as this is my first incubation so i honestly have no idea what im doing. Thanks in advance.