I've got a still air hovabator, hatched coturnix in it before, but this time with my buttons I'm having trouble keeping the temp stable. It seems to fluctuate between 100.5, and 98.2. It always drops if I leave my door open, but even closed all night the temp was lower this morning than it is now. What is a safe range of temp fluctuation, if any? And is it true that if the egg "sweats" in the incubator, it is infertile?