She seems young for pendulous crop which is due to overstretching of the crop from eating too much. Impacted crop can result from eating long grasses that get tangled in the crop. That can rot and lead to sour crop. Since the crop does not smell bad yet, her crop may just be slow in emptying. You haven’t said yet what you feed or if they get a lot of treats. Be sure you do put out grit. Many think that oyster shell is grit, but they need granite grit available.
Hopefully with all of the suggestions, she will be alright. I haven’t had good luck with the few crop problems I have seen. I did not see any problems for the first 5years, but have seen a few the last few years. Look for any other symptoms, since coccidiosis and other illnesses can slow the crop.
Concerning my own hen, I'm already treating her for just-in-case coccidiosis; I hurried to a vet as soon as I saw a tiny bit of blood in her poop.
However her diarrhea has not stopped, and her crop is just as big as before. The bloody poop did not reappear while under vet examination, so I'm awaiting the fecal test results to see what that was all about. (8 days later, still no calls....)
I give my chickens home-made poultry feed from a local farmer, it's always worked well before, no problems on that point for my layers. The one thing I didn't know about back then was grit, which is surprisingly hard to find. I only have one store coop close to my house, and it said it sold poultry grit, but when I opened the sack it was full of grains and I didn't see any rock pebbles that would belay the presence of grit in there.
As I understand, grains aren't good for chickens with crop problems, and I can't find pure poultry grit anywhere close by, so I'm at a loss on what to do on that front. (I can only drive to fetch the grit, as financial walls are keeping me from ordering some by mail or online.)