Outdoor rabbit runs must be designed to protect rabbits from predators, as fright from predators causes fatal shock even without direct contact.
Predator-induced fear is acutely distressing for rabbits. The sight or smell of a predator can cause intense panic and fatal physiological stress even when the rabbit is not physically harmed. Outdoor access is valuable for welfare but only when genuinely predator-proof enclosures are provided. Many rabbit deaths from predators or shock could be prevented by better housing design.