Day 20: Yolk sac completely drawn into body; air cell pierced, followed by functioning of pulmonary respiration; embryo makes sounds; chorioallantoic circulation, respiration, and absorption decrease; embryo may pip shell.
The Embryo looked like a day 20 embryo but very small compared to the egg. What I think what happened was a bantam rooster mated with a larger hen giving a very small embryo.
I know you've gotten a lot of flack for your experiments, but I think they are absolutely fascinating! Good for you for thinking 'outside the shell'! I can't wait to see what the next batch brings!