So, in truth I haven’t dealt with Sour crop, only pendulous crop (hence why I know so much about vomiting hens). I have only touched on research for sour and impacted crop. I just read through the some BackyardChickens and backyard herd forums and got the same things. The only treatment that I was able to find that seemed to have the least backlash was in the video I sent previously. Also forgot to mention, if her crop seems full for a while, massage it to stimulate, but not for long, so she doesn’t vomit.