Humidity on the GQF hygrometer says 90! Should I crack the bator and let some out? I don't want them to drown

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I've got a clutch of about 10 eggs under a year old buff Orpington who is broody for her first time. I'm on my 3rd day for half of them, and 2nd day for the other half. It's my first time ever hatching so I hope I get at least one chick!
Humidity here today is 54 outside. What are safety holes? I'm always willing to take adviseI have a friend who says he won't help them...either they hatch or they don't. He just had 4 out of 29 hatch! Maybe he should have intervened