I have a hovabator and just ordered another one. They both have the plastic trays in the bottom where you fill one tray for the first 18 days and both for the last three. I bought a digital temp/humidity from walmart. But if I feel the trays is it that important to measure the humidity. And another question has anyone ever used one if those indoor outdoor thermometer with the cord. I seen one at lowes for 12. I was thinking would it work if I put the device in one bator and ran the cord in the other one. Would that give me correct reading in both bators? I figured that would save me a little money on buying two thermometers.