Actually, both species (sun bear too) are kept poorly here. The pair of sun bears have two small enclosures opposite this one, but the separating door is left open at the moment, so they have more space to pace around.
A lot of places do keep them well, and I've seen some enclosures which are of a very high standard. Phnom Tamao (Cambodia) actually has a collaborative project with free the bears foundation, and they hold over 150 rescued bears on site. The display enclosures are good.
