You shouldn't be stagger hatching (putting in an egg a day) unless you have another incubator you can use for lockdown. For the last three days of incubation eggs have different requirements - higher humidity and no turning. Eggs on days earlier than 18 still need to be turned and need lower humidity or they will not lose enough moisture and the chick will drown in the egg. If you are getting one egg a day, store eggs for ten days (after ten days fertility starts to drop) then put all ten in the incubator, wait until they hatch, and repeat. Or get another incubator to use exclusively as a hatcher. That's what I do