I have seen gut strings being made, directly at a freezing plant. It required a specialist, in this case a gnome-like character who twisted the gut according to the section of intestine it came from. His apprentice, much younger, started on stretching and making condoms from the same intestines. The old fellow told us some Germans preferred the gut variety rather than latex. Was he pulling our legs or is it true?
Anyway it seems that manufacturing gut strings is a specialist job like many others which are dying out.