If she already has sour crop, these treatments are not enough. You need at least to give her Miconazole to treat the yeast. If you know how to tube feed, please start epsom salt flushing right away. Always give her probiotics and add apple cider vinegar in her water everyday.
I currently have a hen with slow crop for 4 weeks, and her crop finally gets almost flat last a few days. I gave her Miconazole first with coconut oil and massaging, didn't work. So I start epsom salt flushing followed by acidified copper sulfate treatments. Still didn't work. Molasse flush. Didn't work. Tried stool softener (Docusate Sodium 100 mg), then her crop start getting smaller. Restarted epsom salt flushing followed by acidified copper sulfate. This morning, her crop was almost flat with very few fluid in it. I think it will go back to normal soon. She's only allowed to eat baby chick feed and wears a chicken bra this whole time. And she gets coconut oil (or olive oil), probiotics, apple cider vinegar, and massaging every day. I don't know what really helped, but it took really a long time before I saw any improvement. By the way, I know my hen doesn't have reproductive issues, since she laid eggs the first weeks of treatments and last two days. Good luck with your treatments! Hope your girl getting better too.