So, day 18. This is the day (it doesn't matter at what point during day 18) that you stop those eggs turning, bed them down and higher your humidity and start the nail biting.
Most people that incubate with an automatic turner, especially the sort that you use with the styrofoam bators, take it out. Now is the time to fill those water wells. A mesh screen usually covers the bottom. I use a rubber shelf liner over my screen to lay my eggs on.
This is the time to do your "last" candling and mark those air cells. When you place them in the bator, place the side of the egg that has the lowest dip of the air cell face up. Usually when a chick pips it will pip near to that dip. Once you have them all candled and marked and "bedded down" close the incubator and take a deep breath cause now all the worrying is about to increase tenfold.
Once the incubator is in lockdown, give it some time for the temp to regulate and the humidity to level out. Then make any adjustments that you need to get the proper temp and humidity for the upcomming hatch.
Proper temp and humidity for lockdown/hatch
Humidity is something that definitely needs to change with lockdown and hatch and just like everything else......that's right, people's preferences differ. As stated in my humidity post, some of what you should take into consideration is your habits and hatching phillosophies. Many people and many incubation resources will tell...even demand, that YOU DO NOT OPEN THE INCUBATOR AFTER LOCKDOWN. Yeah, ok. In one ear and out the other....seriously though, there are those that have a strict hands off philosophy once they go into lockdown. I have often seen this one person say, "I'd break anyone's hand if they opened my incubator after it was in lockdown." Whatever..... The point is if you have a strict hands off philosophy, then more than likely you can lockdown and hatch at the recommended 65% (or lower) humidity recommendation. After all, nothing is going to effect the humidity other than the drying of surface area. And hands off people usually have ways to add water w/o opening the bator.
If you haven't gotten the gist of my personality, it's soooo not hands off. Patience (in abundance) was not something God found neccessary to give me. My patience and self control are tied up in being a single mom. I am a typical meddler. My eggs need to be where I can see them. I use sponges in my bator for humidity that need to be re-wet from time to time. I (gulp) remove my chicks after they have hatched and get active. I also remove the shells and I am willing to assist if it is neccessary. I do all this and have NEVER had it affect a pipped/hatching chick. I also keep my humidity 70-75% for hatch. If it starts getting to that 65% then I am wetting my sponge and raising it back up! I use 2-3 sponges in the bator after lockdown and instead of dealing with refilling wells, I just re-wet the sponge(s).
Note: Condensation in your bator means your humidity is too high and you need to cut it back a bit.
Bottom line-if you are hands off, you can get away with less humidity, if you are not so hands off and open the bator periodically, a higher humidity is going to be your safety net.
Now you have to do some more waiting...