Went on lockdown yesterday morning. This morning I noticed a few pieces of shell laying on the liner inside the incubator. We watched the duckling moving around and the hole got bigger and bigger. Peeping louder and louder. Then nothing. I waited about half an hour and picked up the egg and the duckling was dead. This was very frustrating and saddening. The temp had been about 98, humidity kept about 70. I'm thinking he suffocated. I guess I should have helped him but everything I had read said to leave it alone. Now I have another with a few pieces of shell broken off and the membrane is showing but intact. I see nothing going on with this one. I'm just feeling a bit lost.
First time hatching.
I'm not sure if there is a hard line rule, its really a judgement call. I personally allow up to 2 days after the expected hatch date just in case. Some might wait a few days longer, the only thing you have to be careful about is a bad egg leaking in the incubator causing bad bacteria to get all over in there.
That was the scariest parts of incubation in my opinion. The last thing you want to do is pull a live egg because you think you lost it and end up killing it.