@Therabu I recently posted about Mouse-deer, aka Chevrotains, in my 'Mammals' thread and many zoos don't know what species they have. Mouse-deer taxonomy is complicated and so I don't know if these guys are pure. @twilighter and I saw Mouse-deer more than a dozen times in our 3 weeks travelling throughout Southeast Asia, and we even hand fed them at Lost World of Tambun (Malaysia), but the taxonomy is muddled.
That is a Bonanza! I've only seen mouse-deer / chevrotains a handful of times, but I've never seen a photo with this many animals in one exhibit. For some reason, I always assumed that they had to be kept in pairs! Thank you for sharing this photo!