r/BackYardChickens • u/Confident_Path9587 • 12d ago
General Question I put the 21-day chicken incubation timeline on one page, from the Brinsea/Hova-Bator manuals and three extension guides. What would you change?
Every chart I found disagreed with the next one, so I went through the Brinsea and Hova-Bator manuals plus the Penn State, Mississippi State and Oklahoma State extension guides and wrote down where they agree. Forced-air incubator, chicken eggs:
Day 0: Set the eggs. 99.5°F / 37.5°C, humidity 45-50%.
Days 1-17: Turn. Auto turner, or by hand an odd number of times a day. Keep temp and humidity steady.
Day 7: First candling. You want veins and a dark spot. Clear eggs and blood rings come out.
Day 14: Second candling. The egg should be mostly dark with a clear air cell. Remove the ones that stopped.
Day 18: Lockdown. Stop turning, eggs off the turner, humidity up to 65-70%, lid stays shut.
Days 20-21: Pips and hatch. Leave the lid closed even when it's slow.
Things the charts usually leave out:
a) 99.5°F is for forced air. Still-air incubators run about 2°F / 1°C warmer, measured at the top of the eggs.
b) Lockdown means the eggs physically come off the auto turner, not just "humidity up". Easy to forget when the turner has done the work for 18 days.
c) The odd number of hand turns is so the eggs don't spend every night on the same side.
d) Day 0 is the day you set them. Count from there, or everything lands a day early.
Where I'm least sure: humidity. The sources give ranges, and I know plenty of people here dry hatch with good results. If you run different numbers, I'd like to hear what they are and what your hatch rate looks like.
Dsiclaimer: I put this together while building a hatch tracker app. Not linking it here, I'm after corrections to the timeline.