While the chat is about potential ungulates, my absolute top personal pick would be one of the chevrotains. They would add something unique - very small animals, able to be kept in walkthrough enclosures and in indoor displays such as tropical and nocturnal houses. They could also do with a similar animation to hippos; while they do swim, when they move around underwater, they do so by walking along the bottom of the pool or river. The South Asian species are, to my mind, the most beautiful of the entire chevrotain family.
In terms of exact species, I keep erring between the
Indian spotted chevrotain, a fairly widespread species from India that is kept and bred in a fair number of Indian zoos...
...And the
yellow-striped chevrotain, which lives only in Sri Lanka but until fairly recently was kept in big numbers in several of the zoos of Singapore.
