This is one of 5 cards I have of Chi Chi, I think this one was when she was still small and living perhaps in one of the small circular pits near the Lion House? (Not sure on that but the brickwork looks familiar?). Two or three show her in the semi-circular grotto-style enclosure she lived in for a long time near the Clock Tower/Camel House. None are from the Cattled Sheds enclosure though.
@Pertinax
Indeed "Chi-Chi" was originally housed in a small circular pit near the old Lion House that was subsequently converted into a seal pond. I don't know of any postcards depicting "Chi-Chi" in her enclosure in the Deer & Cattle Sheds.