I don't know if this is helpful but...
Recently on another thread someone had posted there was a study done with shipped eggs. They let them "settle" for 24 hours and then placed them in the auto-tuner TURNED OFF, but set so the eggs sat perfectly upright in the incubator. Essentially the study found if you let them sit for the first 5-7 days in the incubator but not moving in the auto-turner (or egg carton), you will have a better hatch rate from shipped eggs. This "stillness" gives the air cells a better chance of re-establishing themselves in the proper position.
I tried that with the hatch I have now, but call it conditioning...I just couldn't let the eggs sit still for more than two days. I know! The study concluded better hatch rates -- up to 70% hatch rate I believe, but I still worried about the embryo sticking (although how does that happen when everything inside the egg is wet and slick?) or the embryo not developing properly from being in one position.
Here is the other thing. The auto-tuner is constantly ticking which means there is minute but constant movement of the contents of the egg. And if you have a forced-air, the whir of the motor also contributes vibration...
I think with shipped eggs there are so many factors you can't control from how the eggs were handled or what conditions they experience before they reach you, to the nutrition the parents received which contributes strongly to egg fertility and embryo viability.
Some people don't let the eggs settle at all as a practice. I suppose they must get something to hatch if they continue to do that. It can't hurt...or does it?! Hahahah.
(Edited to fix the hatch rate percentage. It was 70 not 50)
Edited by ReikiStar - 3/22/12 at 8:29pm