How's your hen? I'm dealing with a similar situation here. Frustrating!
Hi! Sorry you are dealing with this too! It has been frustrating! So it’s been over a month, probably almost a month and a half. She’s acting completely fine and normal. She’s very active, laying eggs almost daily, and really fights me when I try and pick her up.
I took her to a vet about an hour away from us, as we have no vets closer to us that will see chickens. They found that she had a ton of grit in her crop and were able to flush it out. Not sure if she knows there is something wrong with her crop and she was eating more grit to help break up whatever was in there and then she ended up with too much? But the vet also helped her to vomit everything else up and it had a terrible smell so she def has sour crop. They gave me a prescription for nystatin but I haven’t filled it yet as I found medistatin online. The vet said I can use that if I want and gave me the script for nystatin if I’d like to use that instead. She told me to give her the medication twice a day for 7-14 days. You can buy medistatin online. I don’t have my dose on hand as I’m out of town and my parents are watching her, but it’s about 1/2 teas twice a day.
I spoke with her vet yesterday on the phone to update her and she doesn’t like that her crop is still enlarged. I told her that I think her crop may be a tad smaller, but even in the morning it still feels like a water balloon. I have her scheduled for next Thursday to take her back to flush out everything again and I’m going to take her medication with me and ask them to dose her as well as she fights me so hard when I try to feed it to her. She said I can call her back if she seems to improve and cancel the appointment. I’m also hopping she improves because she fought them so hard last time, the vet said they may have to use a little gas to calm her down so she doesn’t fight them as much. I’m def a little worried about any anesthesia. So praying she improves before then!
It has been frustrating because it’s been so long and I’m worried she will have pendulous crop. I have tried multiple times to put a crop bra on her, watched videos and read articles on how to properly put one on her, and gotten help holding her down and she will not keep it on. She throws herself against the wall, flops around, and almost strangled herself trying to get it off

. She was so dramatic lol. So I stopped trying for a bit because she was starting to become afraid of me. She’s always been one of my friendlier hens and now she’s not letting me get too close to her, which I don’t blame her.
Anyway, sorry this is so long! I had another hen who had sour crop a few months ago and I healed her with just the monostat suppository method. I’d give her a third of the suppository, melted over a scrambled egg, and she ate it. She was better in about two weeks. But you can get medistatin online. I googled the dose and compared it to what the vet told me and for a hen who is about 5lbs you’d give 1/2 teas of powder twice a day. I mix it with water and syringe feed her on the side of her beak. But now with her fighting me I’m sprinkling it on her egg.
Ok I’ll finish now since this is so long, but hopefully this can help you a bit! Let me know how your chicken is doing!