Is it better to lockdown early or late ?

[tiedyechick]

I am incubating in my classroom. Day 18 falls on a Sunday morning.
Is it better to lockdown on Friday day 16 or Monday day 19?
Or is it super important that I lockdown on day 18 the Sunday?

 

[junebuggena]

Day 19 would be better, and you'll be there to monitor it better to keep it as stable as possible. Raising the humidity to hatching level at day 16 might cause some chicks to drown in their shells.

 

[sumi]

Locking down a day later would not matter. I've found early birds pipping in my incubator once when I went to lockdown and they hatched out fine. The humidity is very important once they start hatching, but a day or two too soon, may cause problems, as the above poster said.