Best of luck to you both! It extra sucked that the last full egg she ever laid was a healthy hard good egg, just encased in bad. Here's hoping yours is just figuring out her groove still <3
Re-update, the next day she got worse. Sometime during the early afternoon, Jumbo got herself a severely prolapse vent with a partial soft egg coming out at least 5 hours ahead of schedule. Between her ongoing egg struggles and the extent of the harm, the only humane choice was to cull her...
She got it out! We gave her a full Epsom bath over her vent, which involved a lot of her jumping to break out of the lidded bath - an overturned colander on a large flat-bottomed mixing bowl. Still no egg and the water was cooling, so we put her with her sisters and made a humid/warm setup for...
This is that cracked egg and previous post:
https://www.backyardchickens.com/threads/a-curious-case-of-cracked-quail-egg-anecdote-not-emergency.1535924/
The next 5 or 6 eggs were slightly were weaker, then they started getting arguable a little stronger, but never a sound egg yet.
Edit: resolved, seems okay, photos below.
TL;DR big quail lays big weak eggs. Didn't lay yesterday but had one in the chamber. Today the egg is bigger, but still very weak and still inside.
I have a quail who is a hefty girl, easily 20% larger than the rest, and she lays some hefty eggs, but...