You're absolutely right, but there's always that one fluke chance that throws everything off. I had an external pip where the membrane looked intact, but wasn't. Apparently, the baby was slow and the membrane dried out, sealing the "flap" so that it looked solid again. The chick could have gotten out easily enough, but air couldn't really get in. It rested long enough that I was worried, so I oiled the membrane and made a tiny air hole. I don't know whether that made a difference or if handling the egg woke up the sleeping baby, but we had a chick within the hour. That's the only reason I questioned it ...Impossible. The membrane is pipped if the shell is..