I have 3 Muscovy duck eggs in the incubator. One of the ducklings has already hatched, the other one is zipping and my last one hasn't externally pipped in 12 hours after he internally pipped. He's still moving and the egg is rolling around occasionally. I want to know when I should start worrying and taking action to help the duckling? Will he suffocate if I don't make an external pip for him?