If you have any experience with incubators, you know that about three days before the due hatch date, you put it into lockdown. This means you raise the humidity, stop the automatic turning if you have it, lay the eggs on their sides if they were upright, and firmly close the incubator up, not to open it back up until the hatch is finished. Opening the incubator during hatch lets the humidity escape, which can cause chick deaths.
Here is my routine for putting my Brinsea Octagon 20 ECO Incubator into lockdown. (sorry for the bad lighting. The incubator is in a dark spot in the room).
Here it is on day 18, just before lockdown. I have removed it from the turning cradle. You can see the dry sponge I use as a spacer when there are not enough eggs to complete a row. This keeps them from unnecessary rolling and bumping when the incubator tilts on the cradle.
STEP 1: I have removed the rails.
STEP 2: I carefully transfer the eggs to cartons for safe-keeping while I finish getting the incubator ready.
STEP 3: I fill the wells to the top with warm water and then use a rail to hold wet sponges upright against the back wall. The sponges will help provide extra humidity.
STEP 4: I then add a second rail about 1/4″ to 1/2″ from the first one. This keeps the eggs from resting against the wet sponges.
STEP 5: Hatching is a messy business. I line the tray with paper towels.
STEP 6: I carefully place the eggs in on their sides.
STEP 7: I have placed the top firmly back in place. It will not be removed until a day or so after the hatch has finished.