They certainly look good in a big group like this. Its the same enclosure I saw them in but they may have had to enlarge it by now.
It's grown since then, too - two new piglets there when I was there last month and a certain keeper there confirmed to me that the group now stands at 15. Pretty impressive.
ISIS lists 14 animals; however, I would trust Maguari rather more than I would trust ISIS. Duisburg is also down for 14 hogs; so too is Pretoria. With an animal this fecund, it must be fairly easy to build up a big group if the facilities can cope. I find this Woburn enclosure rather unsatisfying. the fences are quite high, so it can be hard to get a decent view - for children especially - and it's not exactly a thing of thought-out beauty. More just a patch of land with a fence around it.
Why thank you! As I say, the figure is direct from a keeper I know personally, so it should be reliable!