Help with Thermometer in new Incubator

[Porterfive]

I have just put 30 RIR eggs in the incubator, a new Hovabator. Before I put the eggs in the temp was consistantly 100. Now I have the thermometer that came with the incubator sitting on the eggs as instructed and a digital thermometer on a spare space on the turner rack.
The digital reads 98 and the other reads 103 sometimes 104.
Which should I believe??
Can anyone help, don't want to cook my new potential babies.
Thank you. Jenny

 

[jnjross]

how old are the batteries? i was told to put a new one in at the beginning of every hatch so it won't poop out half way throu