Since it pipped at the wrong end, it never got to internally pip. That means that all the time it would have spent resting after the internal pip plus all the time it needs to spend resting after the external pip are going to be lumped together. It will take probably at least 48 hours before it zips and very likely even longer, since ducks are slow hatchers. When they are in this malposition, most of the time they can hatch on their own and help is not needed.
If, however, it gets to the point that the other eggs are hatching out but this one still hasn't, then maybe it will need some help. In which case you can refer to this article:
https://www.backyardchickens.com/articles/guide-to-assisted-hatching-for-all-poultry.72886/
If, however, it gets to the point that the other eggs are hatching out but this one still hasn't, then maybe it will need some help. In which case you can refer to this article:
https://www.backyardchickens.com/articles/guide-to-assisted-hatching-for-all-poultry.72886/
It may take a day or 2 to get it's legs up and going they are pretty squished in those eggs.
