This works for me..
I found that not bringing up the humidity until internal pip helps them. I incubate at 100 and hatch at 97. I live in a humid environment. You need to find the perfect humid and temp environment for
your home for good hatching. My numbers might not work for you. If you live in a humid climate you need less humidity, if you live in a dry climate you need more. My hatches work best for the chicks on lower temps. They have more vigor and are less likely to die early from complications. Some have very good successes on high temps. This is just my person experiences. It also depends on what type of incubator you have. I have table top incubators. The best one I have found so far is the Genesis. I have $400 dollar ones that are not as reliable or as successful. I usually have 100% hatch with my own eggs. I do not remember when I lost a chick from my own eggs.
I do not add any water at all in my Genesis. My humidity is around 30% with out water. If it does drop below 20% I have added a damp sponge. I do add water when the incubator starts cheeping, and raise it up to 50%. When chicks start hatching the humidity goes up on it own. I have also gone into the chick room and found chicks hatched out of eggs still in the turner with out any added water.
Sometimes those lil ones hatch early.