It really kind of depends on how you handle them while out of the incubator. I put mine in a flat tray on a towel then put a towel over them so they don't lose heat too fast, then I candle them in a warm room, knowing what to look for well in advance so as not to sit there with the egg over the hot light for longer than 10 seconds. Handling the eggs gently not rough and jarring, return them to the bator and no harm done, you could keep them out for 30 min with out a problem.
AL