Yes you can open the lid. My incubator has a cool down option so when set it turns the heating element off whatever time I set it for.
Humidity will depend on how your air cells are developing. I start off with it at 45% and adjust accordingly. If air cells look too big at candling I increase the humidity. If they look too small I decrease the humidity.
Misting the eggs, I use a spray bottle to spray the water on the eggs. I do this just after cooling as the incubator is warming back up. This replicates the goose leaving the the nest going off to eat, drink and swim. She would be wet getting back on the eggs so the misty replicates this.
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