Eggtopsy photo and questions

[Susan10]

This one was alive and moving upon day 26 candling and moving into lockdown. Day 29 I saw egg wiggling. Day 30 candled and no internal pip. Day opened air cell, no internal pip. This is what I found with the aircell and its surrounding shell removed. It seems like the chick was not in a position to break into the air cell but rather into the side of the egg. But oddly, the inner membrane was thin and papery with no blood veins, seemingly ready to hatch... Yet the yolk sack was not absorbed. What could have caused this?

Photo here: http://img.photobucket.com/albums/v394/dreamwave00/Mobile Uploads/image.jpg