We use two hygrometers. Depending on the type of chicks I am hatching, I either do a dry incubation and 60% lockdown or 45% incubation and 65% lockdown. When you are doing a staggered hatch, you can drown chicks in the shell if the humidity is too high, and you can shrink wrap them if the humidity drops too much by opening the incubator to take hatchlings out.how to you measure your humidity?