I'd like to disable pets for inactive sims mainly because I don't like people owning horses when my neighbourhood or their house does not support horses.

I've got story mode disabled including pet population but that doesn't seem to stop people from getting pets.

I'm looking in the GameplayData.package and I think I need to edit the PetPool string.

I'm going to play around with it but I thought it a good idea to post this incase anyone else could help, unless there is a mod like that already, in which case great.

Any help would be greatly appreciated, thanks.

If you have nraas Story Progression:
From City Hall or A Computer Access Story Progression>General Options>Sims>Maximum Residents (Default for all the animals is 25 for each species). Set for horse 0.
It should help.

I don't use NRAAS Story Progression, it does way too much stuff for me.

I've changed all the min and max values of all horse types to 0, I'll now play for a bit to see if it worked.