So you don't see any external pip or anything? Can you candle, see if you see any breathing or internal pip?
Here's what I would do if I was in your situation:
I would inspect the egg for a pip spot first.
I would then candle and look for breathing second if I saw no pip.
Then if I saw no breathing or sign of life, I would open a small hole in the air cell that's just large enough to see through.
If you look through the aircell and see white membrane, then look for breathing movement on the membrane.
If you see no breathing, lightly moisten the membrane with a q-tip or similar and see if you see active, red veins.
If you open a hole in the aircell and don't see white membrane when you look inside; the membrane is transparent so you can see the chick, then the chick has died.