Zipping
From that second external pip, the chicks “zip” by turning around inside the egg while breaking through the membrane and shell repeatedly in order to be able to remove the top of the egg and hatch out of it. It’s a little like a really slow motion zipper on your coat, but using all your strength to break free. Once it is mostly zipped open, they give a few strong kicks and push themselves out of the egg shell. Finally free, they’re very awkward and look like tiny wet dinosaurs, but they’ll be fluffy and cute in no time!