Well actualy reptile eggs are way more versatile and complex than you guys think
Wille they are fertilized, inside mom and for 24 hours after they are layd, they are still no atached to a defenitive possision, so the gem can kind of float inside the egg´s shell, embrio on top and if the egg is turned the gem goes rigth back in place. But after thouse 24 hours there is a risk in turning the egg and the risk tends to increase as the incubation goes on, untill the last week in wich it tends to not matter much. Of corse all of this is teory
And Ive seen turts and toises haching not rigth side up and no ill efects
So what I recomend? Try with all means possible transfering the eggs to the incubator in about the same possition they were laid, but dont be krazy about it. I also dont recomend marking the rigth face of the egg with a pencil or anything, I think that can have hill efects on the embrio. Also handle eggs the minimum possible and be carefull to what you call a bad egg. If you do that Ill tell you good egg will hach. A very good process is also leaving the eggs were they were found(considering of corse that the adults can be transfered or that they cant tuch the eggs) Many baby turts hatched naturaly in the vegetacion full areas that soraund my pond
I just dig the nest, remove the bad eggs, take away roots, debrys ,etc, close the nest and put a small mesh cage on top of it
, never paid particular atencion to that (but I make shure every one had more or less the same face rigth up) and many times all of the eggs hached
