I tend to put safety holes in the air cell if it's been 24 hours since internal pip. It provides air for them in case they really can't pip externally for some reason, and it doesn't impede the hatching process, so it does no harm.
So, if you wanted, you could make a small safety hole in the air cells of those that are internally pipped. Candle the egg to determine where it's safe to make the hole, I usually go with the top of the air cell. Take a screw or drill bit and gently twist it back and forth on the egg while applying slight pressure. Eventually, the screw will create a small hole in the shell. Please note that this should be a small hole. There is no need to widen it further than the size that is made by the tip of the screw.
So, if you wanted, you could make a small safety hole in the air cells of those that are internally pipped. Candle the egg to determine where it's safe to make the hole, I usually go with the top of the air cell. Take a screw or drill bit and gently twist it back and forth on the egg while applying slight pressure. Eventually, the screw will create a small hole in the shell. Please note that this should be a small hole. There is no need to widen it further than the size that is made by the tip of the screw.
