I always do eggtopsies on any eggs that don't produce a happy, healthy, fuzzy chick. I even microwave the non-fertiles and feed them back to the chickens. This early quitter seemed especially interesting. It was a 7 day old embryo which appears to have developed its brain without a cranium.
Thanks for sharing the pictures. It's amazing how much they develop each day. First photo, day 7 and second photo, day 9. You can even see the little beak in the day 9 photo!