@SivatheriumGuy No they are very uncommon (spotted hyenas are more common). This is the only US zoo that I personally know has them, though there may be a couple others. If anyone else knows please report the locations here.
Striped Hyenas are only found in maybe 5-10 zoos in Europe as they are extremely rare in captivity. In North America they can be seen at the Living Desert Zoo as well as Fort Worth Zoo, and perhaps the odd non-accredited facility. I remember seeing a couple at Zoo Boise a decade ago, but Spotted Hyenas are far more common in zoos worldwide.
@snowleopard according to zootierliste there are 44 collections in Europe with Striped hyaena, and if you include the Middle East then it rises to around 50ish collections. So not really common, but far from as rare as you initially thought.
@snowleopard you probably were, the two species combined is probably about 7 holders total. I only bothered checking because I'm trying to entertain myself during this situation!