Ok... What about 40% the whole time? My problem is that I have hatcher in my huge fridgebator but humidity stays the same throughout the entire bator.... So whatever humidity is in the hatcher is also what humidity the eggs are incubated at. I believe lacrystol did a test with not changing anything dring lockdown?
Results will vary depending on location, altitude etc so what works for me may not work for you. I've heard of several people incubating at higher humidity but it doesn't work for me. 40% is definitely too low for hatching though