Is the chick still gasping/yawning/chewing? If so it is still absorbing the remains of the yolk and that's the most critical stage so leave it be until you no longer see it doing that. They can take up to 24 hours from the first external pip to fully hatch, but with that much missing shell the chick may need help once it's ready to unzip the egg.
Here's an article to read through while you wait so you know what to do if you need to assist:
https://www.backyardchickens.com/articles/guide-to-assisted-hatching-for-all-poultry.72886/