if you have a very dark room, a very bright light (a 7 or 9 LED flashlight is great) you might be able to see something, but don't count them as duds just yet, I don't remove eggs I'm not sure about till day 18 without any problem
when you use a LED flashlight don't forget to add the tape around the light so the light doesn't escape around the egg
when you use a LED flashlight don't forget to add the tape around the light so the light doesn't escape around the egg