Ours has been very touchy too. We are doing a dry hatch and our humidity has risen to 50%. This is mainly because is has been raining for the last couple of days. Besides removing all of the water from your trays I don't know what else you can do. A wise member on this thread assured me that broody hens hatch chicks all the time in areas where the humidity is very high. Put my mind at ease a little bit. Short of turning on the air conditioning in the middle of winter, I don't know what else to do

. I think as long as it stays below 50 you should be ok.