DID YOU KNOW… that pufflings, like most chicks, have a tiny calcium deposit on the tip of their beaks called the egg tooth? This little hard knot helps the pufflings break open the eggshell. Most birds have an egg tooth and breaking open the eggshell is commonly referred to as pipping. Chicks usually have a muscle just for “pipping” located on the back of their necks giving them the strength to force the egg tooth through the inner membrane of the eggshell. “When a chick becomes too large to absorb oxygen through the pores of its eggshell, it uses its egg tooth to peck a hole in the air sac located at the flat end of the egg. This sac provides a few hours worth of air, during which the chick breaks through the eggshell to the outside. The egg tooth falls off several days after hatching.” ((http://en.wikipedia.org/wiki/Egg_tooth))
I saw a video that had great shots of the egg tooth, let me share some still shots from that video: