My last two hatches resulted in quite a few fully grown chicks who died in the shell never pipped. What is causing this? I was very careful with temps and humidity this last time. Any advice? My incubators are the genesis 1588 model. Using two different thermometers and hygrometers. Seriously thinking about buying an RCom or a Brinsea Octogon 20 incubators - which one would you choose?