Yukkuris are essentially omnivores. You can often see them eating bugs and worms. Thrown out fish heads are not out of the question either. In some comics there are examples of owner feeding their pet yukkuri meat, and they happily eat it.
But you never see them actually hunt and eat raw larger animals, probably because they normally don't have the means to do so.
But let's imagine a hypothetical situation, where a large stray yukkuri finds a heavily injured stray cat. Cat is still alive, therefore not rotting yet so no "uneasy smell". Even if yukkuri decides to finish it off first to avoid scratches (with stick or something of sorts), it will not start to rot for a while.
Would yukkuri eat the cat in such a situation? Have not seen any examples of similar situation in comics or stories.