It does sound like she has sour crop. As
@Wyorp Rock suggested, begin with the vaginal cream. I just buy the seven day cream and don't mess with the suppositories. I take the tube, pry open the beak and squirt a bunch into the mouth, sort of like squirting whipped cream into your mouth. Yum! The chicken doesn't mind as it tastes neutral.
Do this again in the afternoon. It's important to do it twice a day, or three in serious cases, for seven days.
You can leave her with her flock. You do not need to worry about withholding food. She will regulate herself. Just don't give her carbs like bread or corn bread, stuff like that.
The Cisapride the vet gave you stimulated her digestive tract. If things don't move after a couple days on the miconazole, a molasses flush would do the same thing as Cisapride.