Thanks for the input, I've recently raised the temp as I've had delayed hatches with poor results. My most recent hatch was great. Not sure why all of a sudden 'this' one would have been too hot. I know that the room has been warmer though - now not freezing with the winter - (in an attached garage - so daily temp does not fluctuate too much but the ambient temp is certainly a few degrees warmer than in the previous hatch. But, one would have thought that the incubator would have been able to deal with that.
Could be humidity issues too, I will assume that the doors to the outside are opened regularly which causes fluctuations in the humidity. Get a hydrometer that will record the high and low readings. The inside of a house is much more stable as there is a larger area to compensate for fluctuations.