I recently had a horrible failure in hatching two dozen maran eggs. After the 24th day I removed all the eggs and cleaned the bator as usual. Then I noticed something. The little carded thermometer that came with my bator had slid down in the rings! This would mean that what I was reading as 99.5 was actually 110!!!!!!! I was devestated Be sure you check your thermometer if you have this kind to be certain the glass has not come loose from the glue and slid downward on the card or you will be in the same pickle I was. Hope maybe this will help someone from loosing a batch cause of this.