Since most of the jobs are in both cities of Los Santos and San Fiero (other than some jobs like crane operator which isn't in LS) why shouldn't butcher be there aswell? San Fiero should have all the jobs since it's the civilian city so it should be there.
After driving around San Fiero for some time I've found a spot that I think is a good place for a meat factory:
Show content
(https://i.ibb.co/0X41dkZ/mta-screen-2023-02-24-19-24-33.png)
Current co-ordinates X,Y,Z,R,Dim,Int: -2267.5134, -156.0157, 35.3203, 90, 0, 0
I might have missed a better spot so this might not be the best spot for it.
We just have to replace the interior from this non used martial arts interior to the meat factory and remove the signs.
Adding another instance of Butcher job would require rewriting the entire script.
Either we move the marker from LS to SF or we make no changes at all, you decide.
I'd say move it to SF for what Blue said, and since Civilians are in SF it would make more sense for it to be there and not in LS