I try to keep mine between 60 to 70. Mine that are in lock down started off a little high 80% due date tomorrow humidity now 70% and I have pips now. I find the eggs are thirsty right before hatch and I've always had to work hard to get my humidity up to 70%....I go by the air sack to decide on what humidity but I live where it is dry lucky to have humidity of 35% even if it rains. I just hope this hatch goes together last time I had an early bird and I had to take him out and shrink wrapped the last one to hatch because it took 4 days for them to hatch.