Actually... there is no need to worry about a lockdown. Don't HOLD the incubator open, but you can open it long enough to grab a chick to put in the brooder. It won't affect temperature and humidity enough to cause alarm. If you're worried about humidity, use a spray bottle to mist the air directly above the eggs (but not enough to make the droplets completely cover the egg shell as they fall), and then close the incubator again. The temperature can also fall a degree or two without any damage.
I also don't stop turning my eggs. I have noticed a significant increase in my hatch rates when I leave them in the automatic turner. And since doing that, I have NEVER had one pip in the wrong end (where as I had several of those when I removed them from the turner for the final three days).
