people more or less are just scared to. they dont want to rip the eggs, if u catch them within the first few hours there not too stuck and they peel apart fairly easy. i dont recomend it thou if u have never done it thou and they hatch just the same as if they were still stuck together.i dont even mark the top of the eggs because it seems turning them doesnt really matter, but then again alot of people just do it to be safe. the most important thing to me when messing with eggs is humidity to as close as 100% and temps between 86-90.