hi all, i was hoping for some advice. I currently have some eggs in the incubator , Im, using a small covatto still air incubator. the last batch of eggs I tried to hatch failed and I figured the temperature was too low. the thermometer on the covatto i have just has a red line showing where your temp should be at this is supposed to be 100 f. however the last batch of eggs I left go till 25 days. when i broke open the unhatched eggs some had dead chicks inside and they still had some yolk sack left to absorb so i figured the temp was too low. this time i have three different thermometers in the incubator the one attached to the covatto (mercury)reads on the red line, annother thermometer(alcohol) is reading about 98 f and annother thermometer(digital) is reading 104. dont these seem to vary a lot and which one should I trust??? has any body any experience in using the covatto incubators?