Thanks for replying. I just spent an hour and a half researching this with no luck. I am going to post some of the links since I spend much of the time going through unrelated stuff. I didnt read every word on every link that I am going to post so maybe I missed something, but from what I have read, turning a bird on its back doesnt suffocate it or kill it. There are many things involved. Which is probably why I was able to spend hours sitting on the couch with my scovie duckling in the baby position. She never struggled to get up or struggled for breath in fact she was quite happy being an inside bird. (When we got the four white ducklings, I put her outside with them and she is a happy healthy bird).
What I found is that birds breathe differently than mammals. Our exhale is passive. Birds lack a diaphragm so they have to contract their muscles in order to exhale. Birds can get held too tightly and suffocate because they arent able to contract those muscles in order to breath properly. I also read that the airflow through the sacs has a great role in temperature regulation. Maybe what happens with the ducks that get stuck on their backs and die is that they have a hard time contracting those muscles in order to breathe correctly and their temperature drops?? Just a guess..
I will ask my vet this week and reply back. For now I will post the links and if someone happens to read something I missed, let us all know. It shouldnt be so hard to find this kind of information but what I keep finding is brooding information and monitoring the air sac in the egg. In case someone else wants to try and search for the answer, I suggest googling "avian respiration". All in all, a good pet owner listens to their animals. The animal will tell you if your doing something wrong in most cases. I wont train anymore of my birds to lay on their backs while I hold them like a baby, but I do think distress played a big part in the death of the ducklings stuck on their backs.