Three things....
(A) STEP AWAY FROM THE INCUBATOR!!!
(B) Yes it gets darker over the course of the incubation period.
(C) once you candle at 7 days, dont do it again until day 14. there isn't going to be THAT much change to begin with, and by taking them out of the incubator daily, you are increasing the chance of aborting the embryo.
(A) STEP AWAY FROM THE INCUBATOR!!!
(B) Yes it gets darker over the course of the incubation period.
(C) once you candle at 7 days, dont do it again until day 14. there isn't going to be THAT much change to begin with, and by taking them out of the incubator daily, you are increasing the chance of aborting the embryo.