I'm not totally convinced that lockdown is really all that important.  In our ignorance we did the following:
We had 4 hens go broody at one time.  In the past we have let a couple of hens hatch out their own chicks and it is so much easier than raising the orphan in a brooder.  Mistake #1.  Mistake #2-5:  leaving all the broody hens with the eggs in the general population.  Mistake #10-98:  Not marking the eggs we left under the broody hens.  Mistake #99-eleventy billion:  not realizing chickens are idiots and can't remember which nest they JUST left 10 minutes ago.
We had the biggest mess you have ever seen.  Chickens switching nests, chickens laying new eggs on top of old eggs, chickens sitting on giant tottering piles of eggs trying to cover them all.  After a week we realized this was not going to work.  We cleared out over 90 eggs and threw them all away.  It was sad but we had no way of knowing how old they were or if they were still viable.  Now for our brilliance....
WE LEFT ABOUT 20 EGGS FOR THE BROODY HENS!  We are slow learners.  Fast forward one week later and guess what?  We have chickens switching nests, chickens laying new eggs on top of old eggs, chickens sitting on giant tottering piles of eggs trying to cover them all.
We buy an incubator with an auto egg turner.  Obviously we aren't to be trusted.  I go collect the first 41 eggs I find, the rest get thrown away ::sigh::
We can't stop turning any of the eggs because we don't know how old they are.  We can't candle because most eggs are dark shelled and we are stupid anyway and don't know what we are looking for.
Day 3 we go look in the incubator and there is a fuzzy little chick sitting in an egg holder rocking back and forth.  We high five and move him to our ghetto brooder next to the incubator.  We go work on the pond.  We come back in one hour and remove the poor little fried chick from under the blazing heat lamp.  We raise the heat lamp about 2 feet and blame each other for killing our very first chick.
My husband was obsessed with the hatching eggs.  He would spend hours staring through the little window.  I never could see anything all that interesting in watching eggs rock back and forth but ::shrug::  He could not NOT mess with them.  If any of them even thought about pipping, he yanked them out and placed them in CICU (Chick ICU).  Of course they all got dried from sitting in the shoe box so he had to help a majority of them finish hatching.  The lucky ones pipped while we were at work or asleep.
We did manage to successfully hatch 35/41 eggs over a 3 week period.  Several of them rode the egg turner for quite a while before being removed from the 'bator.  All of them survived and are very healthy.  None of them seem to suffer from motion sickness.  
Moral of the story:  Chickens can survive a lot of our meddling.  They can also survive us "helping".  They can not survive a heat lamp with the wattage of 1000 blazing suns