I have a higher success rate when I candle less often. Put them into the incubator, candle once in about a week, looking for veins. Then leave them alone. Reduces the chance of contamination, drops or cracks of the shell, humidity and heat loss. Sometimes, less is more with incubating. If your incubator does not have an automatic turner, then place a small object like a pencil UNDER one edge of the incubator and move it a few times daily, to cause a change in the tilt of the incubator (and eggs), so that you do not need to open the incubator.