The Internal Pip
It's after this internal pip that the chick starts to learn to breath air and strenthens it's lungs. You may even hear a peeping from within the shell after he/she has pipped into the air cell. Of course, once you hear that pip, you get anxious to see some real action, but hold on. This little guy isn't just strengthening his lungs and learning to breath. He's also resting and he may even be finishing absorbing the yolk. A chick generally starts absorbing the yolk day 19-20. If he has internally pipped early he may still be working on finishing up that absorption.
So how long? However long it takes. At this point there isn't much you can do, even if the chick was in trouble. Everyone hears stories about chicks making the internal pip and dying before they progress any farther. Yes, it happens. However, if you try to do an assist on a chick that hasn't pipped externally, the chances of you doing more harm than good is higher than you actually saving the chick. There's still a lot nature has to do before that little bird is ready to hatch, you can't rush it. Chicks can take a full day before you see the external pip. There are people that get over anxious and will put a "pip hole" as a safety net after a chick has pipped and hasn't progressed. I understand the anxiety, I definitely wouldn't recommend more than that. A lot of hatching is waiting. Waiting and waiting and waiting.
The External Pip
If you are marking your air cells, (which I highly recommend,) at days 7/14/18, you will generally see the chick's externall pip at the lowest dip of the day 18 air cell mark. Don't get too worried if it is below this mark as your air cells do grow and get drawn down after you go into lockdown and before they start their hatch, so it is very likely that he is still right at the air cell where he belongs.
After the chick pips and gets you all excited, it's time to do some more waiting. Now, nature is absorbing those veins back into the membrane and cutting off the vascular system between the chick and the egg. During this process if you were to try to "help" the chick you would probably cause a perfectly healthy chick to bleed out by severing those veins from the chick too early.Trust me when I say, between pip and the next step (zipping) it can take up to 24 hours. Yes, that long. I find my chicks average between 12-18 hours from pip to zip. Not only is the vascular system changing but sometimes chicks still haven't absorbed the yolk and maybe working on finishing that.
Let me show you why it's importanat to let nature do it's thing:
Graphic Pic-chick hatched too early:
This is why you don't rush hatching. This is why you don't interfere after only a "few" hours after the pip. It may seem like a real long time to us, but for them it's doing what needs to be done for survival. Give them the time it takes to be ready for the hatching.