Sour crop

My girl Beebe had sour crop yesterday, I quarantined, fasted her all day, gave her water with ACV in the evening and overnight. This morning her crop feels like it is pretty much empty. Soft but not longer full? I have her a few bites of plain Greek yoghurt.

My question is, now what? Do I let her rejoin the flock outside? She seems perky, but very unhappy to be in a dog crate in the basement.