Thank you. That could be it. I've been feeding the same feed to both the male and female quails for quite some time so I doubt it was in the feed to begin with, but it's possible the feed got contaminated while she was outside or she ate something weird. I just got some new Wild Game Grower feed that I'll be giving her now, and I'll be washing the food bowls and throwing out the old stuff. I also gave her a bit of boiled egg.
She's mostly just sitting in one place (probably due to her foot), but other than that, she's fairly calm and alert. She seems to be a bit better than yesterday.
One avian hospital I've been looking at is booked until mid-December, and the other places won't be open until Monday, so it may be a while until I'm able to get an appointment.
Thankfully I live in CA so it's not as cold as other places, but I've added a small heater in the room where she is.