Glyn, there is so much evidence that breeding is no sign that the particular animals are "happy", or that their enclosure is good, or whatever. Little example, in the Ukraine, Odessa, the pair of elephants are breeding regularly in an enclosure of 1/10 acre of concrete - 400 m². One of the most sucessful gorilla and bonobo breeding groups are in Stuttgart, Germany, in a terrible small, outdated and barren enclosure (indoor and outdoor). Mink breed fantastic in farms in cages not much bigger then themselves without any enrichment. Lions, tigers and bears breed very well in circusses in awful conditions.