From the Himalayan Chews FAQ's page, as long as it's kept dry, it's deemed safe for up to 4 years.
Himalayan Dog Chew
When mine had Bully's, I cut off the part they chewed on & stored them in the freezer in a zip lock bag. IDK if that's practical, but I always bought the long 12" ones, so they lasted awhile even tho I cut them off a few inches after every chewing frenzy session.
