I usually put my eggs in the bator in the evenings so should I consider that day 1 or is it considered day 1 after 24 hours? I messed up on my lockdown on my last hatch and they hatched early by my counting and I killed some chicks by not being prepared humidity wise. Don't want to go that route again.
This is what I'd always heard: If you set before noon you can consider that Day 1. Any time after that, the following day is Day 1. I always set in the evening and consider Day 1 the following day.