Not at all keen with the idea of Jersey bringing in large hoofstock or tigers, lions or even leopards. I believe this would probably open the floodgates to them keeping more large species that are so commonly kept and focused on by zoos everywhere else and again would risk something being lost in terms of character.
I don't really like 'thin end of the wedge' arguments. Jersey isn't suddenly going to become like any other zoo. As @GaryA points out, they have kept cats and not just in the early days of the zoo when the collection was arguably less focussed. I think okapi would be a good fit as @Luca Bronzi suggests, maybe Visayan spotted deer too.