I would try a lower RH as well. I keep my RH around 30% until I move them to the hatcher, then increase it to 70 or 80. This seems extra critical for turkeys and Marans/Welsummer eggs, but I find the blue eggs hatch better at that also. It takes some experimentation until you get used to managing a particular incubator. Once you find the settings that work optimally for you, you can enjoy success for many years.