Well, here is a for-instance: I have two Hovabators: the moving air I use for incubation, as it keeps the temp uniform. The other is a still air and I use it for hatching, as it is less drafty for the chicks. My initial hatch rates were very low, and in researching, I found that humidity is a problem. My hatch rates were 50% or less at times, but once I found a dry incubation method(which used to be here on BYC), I got one hatch at 100% and the others were pretty close as well. It's not just the hatcher, but your environment as well. I imagine in the dryer areas that you might need to add more water to the incubator, instead of less.