If you candle with a good light in a very dark place you should be able to see the very edges of the membranes inside have veins or you should be able to see movement. If you try this and see no veins or movement, I would try the float test. Fill a bowl wih water as close to 99 degrees as possible, let it settle, then place the eggs one at a time carefully into the bowl. Let it settle then watch closely for movement. Live eggs will start to rock in the water within a few seconds. Don't leave an egg in water for more than a minute. Make sure there are definitely no holes or pips in the shell before doing this!
If you STILL see no signs of life, I would carefully chip away a small piece of shell from over the air cell. Try to see inside. If you gently prod the top of the membrane covered chick with your finger or a cotton bud and it doesn't move it is very likely dead.
In this case, personally, I would peel off the remaining shell over the air cell then moisten the membrane gently with coconut oil or another oil and there will be red veins visible in the membrane in a live chick. If there are no veins it is dead, unfortunately.
Others might have different opinions on how much this here intervene but this is what I would personally do and have done with eggs before.
I have to say that it is likely these eggs are not viable, however.
