My hen was a black sex link, and they are commonly stricken with reproductive problems. I have another now, same breed, that is also in a crop bra and is holding her own for now. I hope your hen recovers from whatever is going on. Crop issues can be really frustrating since we can't really see what's going on inside. Parasites and reproductive issues have been the causes of all of my birds crop issues, except for one. That one was really a mystery and necropsy showed nothing except a very odd kink in her proventriculus near where it attached to her gizzard, so I have to assume a congenital defect.
