I've seen Long-eared Owls at Howell Nature Center: Wild Wonders Wildlife Park, Blandford Nature Center, Tracy Aviary, California Living Museum, Cascades Raptor Center, Bay Beach Wildlife Sanctuary and at least a dozen other zoos as I just did a quick search through the ZooChat gallery. It seems to me that they are a fairly common species in captivity, unless the ASDM has a type of subspecies but that seems unlikely.
The owl was only on exhibit a short time before it died. The aviary (which was just renovated before owl went on exhibit) has been empty for the last few months.