I'm letting my ducks go broody, and I was checking on the eggs and two of them had started hatching, but there has been no progress at all since then.....I've candled them, and they're still moving, but I can't hear any peeps or taps....What's going on? I've had ducklings take 2 days to hatch, but they were making progress at least.....These eggs aren't doing anything. Should I be worried?