Has it ever happened that 2 chicks came out of the same egg? I know we've all seen double and triple yolkers, and even eggs within eggs... do any of these double situations EVER hatch out a pair of chicks?
Yes, it's possible. Several months ago there was a long thread and Youtube video with someone who hatched a double-yolker. She had to help the chicks out because they couldn't properly pip and zip.
It's not common though....I've read that many times they don't develop or they can't hatch. I've also read about people who ended up with more chicks than there were eggs (ex. 7 chicks from 6 eggs)...so one HAD to have been a double-yolker.