to all who offer advice, i am willing to listen. recently we built a new bator, (changed from a full sized fridge to a mini); reason we changed, too much temperature fluctuation in the big fridge, between the rows, and too much heat loss. we are into our 5th or 6th round of eggs in the bator, and have only hatched a few chicks. out of 40+, each time, only 2 or 3 chicks hatch, but upon breaking each and every egg, we have about 90% development. and it seems that death or cessation of development stops roughly at the same time, every time. the chick is fully developed,but does not pip. beautiful fat healthy chicks. temp is consistant the entire time at 99.8 degrees on each shelf of the incubator. stays there every time i check, with 3 calibrated mercury thermometers. 99.8. i start the humidity at about 30% for the first 18 days. then up to 60% during lockdown. now i have tried lockdown a couple of different ways. first was moving them to a styrofoam bator, but have never trusted the consistancy of the temps. still would get a few chicks, but most died at this stage. so i started leaving them in the main bator for a while on the bottom of the fridge, but time has come and gone for them to hatch. after breaking a gazillion eggs, i still have the same problem; chicks develop completely, but fail to pip. don't actually break thru. ****IN ADDITION: we have a fan in the top of the bator to keep the air circulating..... WHAT IS THE #1 REASON these chicks are dying? i have hatched many chicks over the years, with foam bators, home made bators, broody hens. i don't get it. what could be wrong this time? they are perfect and complete. any suggestions would be appreciated.