This chick pipped over 24 hours ago. Began zipping last night but no progress. It’s chirps are extremely loud and mature but it appears to not be able to get out. I’ve removed a bit of the outer cap. Should I keep going??
You've begun removing a bit of the outer cap? Alright, I'd recommend leaving it for at least an hour or so and watching for more progress.
If progress is made, great, the chick may hatch on her own now. If no progress is made, carefully remove more the outer shell. It's best to go slow, so once you remove a bit, put the chick back and wait again. This way you avoid piercing any blood veins before they're ready.
You want to be really careful about humidity at this stage, use a warm but damp workspace and make sure the humidity in the incubator (?) is high enough.
(I'm talking from my own experience helping chicks hatch, I've done it only twice before though, one of those being with a chick who pipped on the wrong end. I'm very lucky both chicks survived and thrived.)