An vet, especially an Avian would have all kinds of cases. Not hard to imagine them having a bird that died recently. It may not be a crop replacement, just a skin graft to close the crop.
Anyway, maybe we'll find out more if she posts a follow up. Which I hope she does.
My curiosity is what...
It wouldn't surprise me at all. If you look closely at the wound the edges of skin are pink and clean and not torn - as if an abcess or something had formed a sack that opened up when she was messing with it. "Fell off" had to be something contained inside the crop. It doesn't appear to be...