Bests & Worsts Reviews from Amazon

I'm not one to write reviews. However, maybe this will help others to make the best purchase decision. After using a similar styrofoam model for 6 prior hatches with results ranging from 40% to 75% hatch rate, I purchased this model because of the features. Large Egg capacity, air circulation, egg turner, & viewing windows & of course, price. I read other reviews which warned about not to trust the thermometer & thermostat. I figured that my digital thermometer would take care of any short comings. After delivery, added some water Ran the incubator over night making adjustments to get within the range of 99.5-100 degrees. This took many adjustments quickly discovering that the two supplied thermometers were useless. I added 30 Black Cooper Maran eggs from my own flock, checking and making minor adjustments as required throughout the day. After 7 days candled the eggs finding out that all were fertile. So, maybe all was good? Over the new 2 weeks, I checked on the incubator at least 6 times per day making sure the temperature & moisture were in the correct ranges. All seemed fine. Turned off the egg turner 4 days before the expected hatch. When this batch was started, an additional 12 eggs was put under a brooder hen. On the 20th night the last check on the incubator was fine. Went to sleep expecting to welcome the sound of chirping chicks. On the morning of the 21st day, I checked on the hen. Half her eggs had hatched. Then went to see the incubator, to my horror the digital thermometer read "105"! Not sure why it spiked, but brought the temp back done. Ended up with two chicks out of 30. Will try one more hatch. But not feeling confident.