I've never heard of a snake needing its vertebrae realigned, I can imagine it would happen naturally or unintentionally but I would be extremely wary of anyone practicing chiropractic care/adjustments on any animal or human without a license or having studied it in a medical environment. A lot of damage can occur from people attempting to crack each others backs, necks, or various other joints of the body and people have paralyzed their pets by trying to adjust their spines. A client of the vet I used to volunteer at adopted a cat whose hind legs were paralyzed from it's previous owner attempting to crack it's back.