How long to wait to assist?

[SoggyForks]

One of my duck eggs pipped while I was at school. I don't hear peeping or see much rocking but I haven't seen any progress in at least 4 hours. I'll check again in the morning but should I do anything now? And if there's still no progress by then, should I do anything then? (day 24)

 

[nuthatched]

Most people recommend about 24 hours from estimated pip to assist