Give it a bit longer to pip and just keep an eye on it. As long as it's moving and it can reach the membrane when it's time to pip it's o.k. As for oxygen and breathing, the chick is getting oxygen via the inner membrane (allantois), which is filled with blood vessels (the vessels I told you to look out for). These blood vessels bring oxygen to the embryo and take carbon dioxide away. The allantois also stores excretions, absorbs albumen (egg white) used as food by the embryo, and absorbs calcium from the shell for the skeletal needs of the embryo. The allantois stops functioning when the chick punctures the air cell and starts to breathe on its own. The blood vessels then starts receding and at the same time the yolk sac gets drawn into the chick's abdomen, to provide food for it to live off for the first 2-3 days after the hatch. This happens more or less simultaneously, which is why we look at the vessels and judge by their progress how ready the chick is to hatch.