I have a Farm Innovation circulated air incubator that worked perfectly last spring. I pulled it out the day before yesterday and plugged it in to get it ready for eggs. It held perfect for 12 hours or so and then the temperature reading was changing....up and down drastically every second. I've had 3 thermometers in it to compare and they all read different. 99.5, 97, 100, 104. Any suggestions? The 2 that show humidity level were spot on.