Thanks for telling me you experience with this. Im not sure how cool my incubator is, I did up it a full one degree by this morn. I am going to run out to get batteries for my spot check this afternoon and I will know for sure what Im dealing with. I bought my spot check last April for use in my homemade coolerbator. Since the coolerbator is so big I wasn't using the Hovabotors and didn't bother to check the temps on them. This time I pulled out the hovabators instead of the cooler bator and that is when I found my Spot Check had dead batteries. I have had good hatches in the past so I was in no rush to run out for the batteries. Now I know batteries should have been top of my list of things to do.
Now thinking about it over time I notice that with each hatch in that particular incubator the hatch rate went down a little every time. I assumed I was having issues with my flock of purebreds and thought it was a breed issue. Maybe it was the incubator slowing getting cooler with each hatch and I didn't even notice