The external pip is just a little hole or even just a tiny crack just to let enough oxygen into the egg so the chick can breathe. It may take upto 24 hours for them to start zipping the egg. The best way I can describe it is that they munch and push through the shell in a line around the shell to create a cap that they then push off and then emerge from..
Here's one of my last hatch that has zipped the cap and got its head out of the shell.
Best of luck and keep us posted
Here's one of my last hatch that has zipped the cap and got its head out of the shell.
Best of luck and keep us posted