The mommy duck has better sense than to pickup her precious babies and turn them every which-a-way while they are hatching. If this treatment was good for pipping duck eggs then I strongly suspect that Mother Nature would have equipped ducks with hands on the end of their wings to make it easier to pickup their pipping eggs and play with them. That in-my-humble-opinion is why the eggs in an automatic turning incubator are taken out of the automatic turning device on the 18th day and placed in a hatcher, or at the very least the automatic turner is turned off. A properly positioned hatchling should turn inside the shell scoring and weakening the shell with its egg tooth. A few feeble kicks then breaks the big end off of the egg shell and the hatchling tumbles into view.
Just saying, but I also doubt that it would do a human fetus much good as far as ease of birth, or positioning for birth is concerned if its mommy was hung up by her heels during labor. I know that this is an extreme example but the same concept is at work.
I agree with the Mommy duck having better sense, again, if they are with a momma or in an incubator, it's not going to make any difference where that egg is at, Momma ducks will get off those eggs they will go swimming, they will toss those eggs around. I personally think they are a lot rougher on the eggs then we are, if you listen you can hear them Rattling those eggs when it's time to turn them. If we rattle them, they break. LOL.
but the point being, if you handle an egg, it's not going to affect the outcome, when placed back into that bator. they don't need to be in the exact position, common sense is you don't flip them upside down especially if they have internally pipped. But putting them in an different spot in your bator. that isn't going to make any difference in the world. Flipping them YES, then I can see your previous point but I didn't NOT get that impression to what you were stating..you stated the exact spot..
Example: if you have an egg in the left corner of your bator, the larger end facing the wall with an X on top, you can place that egg ANY WHERE in your bator and still have the same results. It doesn't need to be back in that left corner facing the wall.
If you take that egg and put it in the right corner, facing away from the wall with the X up, it will still have the same results.. The only time when it will affect that egg is if you take that egg and FLIP it so that what was the Top (X) is now facing the bottom of the bator then you will run into problems but to take an egg and place it anywhere in the bator it not going to affect it as long as that egg is in the same upright position as when you grabbed it....so that the X is still up..
and from my experience duck eggs, shouldn't be on an automatic turner unless they are laying down.