Hello!
I’ve heard of twin eggs in a couple different places, but I know that many times they don’t survive. It’s still possible though, and it’s happened before! I’d love to see how this turns out!
I’m not sure if both ducklings will be the same direction within the egg, but if they are each facing toward opposite ends, it’s definitely possible that one will internally pip into the air cell, and the other may pip straight through the shell on the other side. It’s happened with my chicks multiple times before when they are malpositioned with their head in the narrow end of the egg.
I hope all goes well! Best of luck! Keep us updated!