After the 27 eggs - all viable at day 14 - spent 12 hours or more unplugged on day 16. . . One Copper Marans has hatched 3 more are pippin - This is a day early - day 20 - How long can I be sure the chicks that hatch are fine in the bator? What should the humidity be? Should the vent be closed, half or open on the brinsea octo 20? How long once eggs are pipped does it take to hatch or know it isn't going to finish?