Can anyone tell me why there seems to be such a wide range of suggested humidity levels depending on the source? For chickens, Texas A&M suggests a Wet Bulb Temp of 86 which translates to 60% RH. My RCOM incubator booklet suggests 45% RH. The Brinsea handbook suggest between 40 and 50% RH. One other I saw suggested between 55 and 60% RH. How do you know which one is correct and which relative humidity level do you use?