I think they get their oxygen in a kinda similar way as mammals, but through the shell... haven't looked up all that, lol... you can see the h3artbeat though, from right at the beginning... it is really awesome, and it is a pleasure to share as much as we can with you, Julie Bird... one day we will get you a weblet or 2...
That melts my heart so much that you are able to see the baby's heartbeat when she's in the shell. So innocent and makes me happy.
And I really appreciate you sharing RavynFallen. It's fun learning new things in the experience too. You've shown me a recently fertilized egg and recently a baby duck in one. I understand mamallian pregnancy somewhat but never gave viable eggs any thought.
And, yeehaw to my own someday!!