Only other thing to mention, if you get one that's not been through one of the charities, is worms, especially toxacara. Kittens will be excreting it (and possibly lactating mum is too); if they poop on hay that's then eaten by pregnant sheep, it can cause abortion.
But if you're having neutered cats (so no kittens) or kittens which are properly wormed (repeated doses up to six months, I think) and won't get into your sheep-keeping neighbour's hay stacks, all should be well.