I just had the worst. hatch. EVER. I need to do one last batch before the season is over (since I got way less than I was hoping to hatch), but I really want to make good and sure I have this issue set before I try again, because I can't take another incubator full of dead-in-the-shell chicks. Background - I have a Brinsea Mini that has given me near perfect hatch rates twice now (when only counting the actual fertile eggs that developed) But I wanted to go bigger. So I got a Janoel-48. I read that it might not be accurate, so I got a mini thermometer and hydrometer to put inside with the eggs to keep things "real". According to that, the eggs were between 45-50% humidity day 1-18, then up to 75-80% for lockdown. Air cells looked good, they didn't look too low. I put 6 of the eggs under my broody. They hatched fine. (ahem, she stepped on two killing them, but that's another issue) 11 in the J48 died in the shell. One pipped and zipped on it's own and got shrink-wrapped in the shell and needed help to hatch. Two inner pipped but died. The rest died in shell, with most of them having varying degrees of the yolk absorbed. It was heartbreaking. So, the first thing I did was buy 2 more thermometer/hydrometers and did some comparing. And now I'm just confused. I started by verifying the accuracy of the thermometers. The Brinsea has a glass bulb thermometer in it. As per instructions, day 1-18, half of the inner water chamber should be filled. I used this as my control measurement, as it was previously successful. The Brinsea therm read 99* f (37.2*c). Therm 1 read 35.2*c with 65% humidity, Therm 2 read 95* f (35*c) and 66% humidty Then I measured the J48. It has a digital reader with a sensor hanging inside. It showed 39.3*c with 58% humidity Therm 1 read 35.1* c with 68% humidity Therm 2 read 99* f (37.2* c) with 68% humidity Therm 3 has an external sensor that I put down by where the eggs would go, approx. 1-2" lower than the J48 sensor. It read 38.1* c at 56% humidity. (I didn't use therm 3 with the brinsea, as the sensor cord would prevent the top from sealing) So... now what?? Too many different numbers!! Any suggestions, based on the readings, what I should set the J48 to for temp to accommodate for the inaccuracy? And what should I target as my humidity? Is it best to take the readings from down where the eggs are or above them? Because, seriously. I can't take another incubator full of dead chicks.