So I've seen neural crest defects in two day old embryos and always assumed that they would die before fully developing... well.. it is not the case apparently. If you look closely at the picture you can see that there is the chicks brain on the outside of the skull and a ridge in the top beak. The reason for the clef beak and exposed skull is because some sort of developmental cytokine didn't initiate the closure of the neural crest so it remained open. Normally they die but guess this guy made it to the very end, just couldn't pip due to the pressure on the head when pressing up to get out. Hope you heeded the title if you don't like this kind of stuff. It's a birth defect.