Got my first incubator and set my first round of eggs. I spent the frist day calibrating the incubator. I'm sure there's better ones out there, but this is the ONLY local incubator I could buy, so for my first try it should do SOMETHING for me. It's a still-air, manual turn, styrofoam incubator. I got it set so the stock thermometer read 99.5 and set my eggs. I've since added thermometers based on others' recommendation for monitoring temps. Problem; I've got FOUR thermometers in the incubator. One reads 99.5 (the one it came with), one reads 98, one reads 102, and one reads 104. I've tried switching their places to see if it's just hotspot/coldspot, but the same thermometers seem to retain the same discrepancies. How do I know which one to trust? If they're in the 99-104 range, do I really need to worry? Every thermometer is a different brand/kind, 1 is digital, the other 3 are glass.