Pearl Factory, the company that was in DTD is also in Sea World, San Francisco, WDW, Vegas and some other places. They also sell pearls online, including one in a can to mimic pick-a-pearl.
I recently inherited a necklace that needs to be restrung. I'm thinking of putting 1 pearl in a pendant because it would be worn more often than a full set of pearls. Maybe you can acquire a pearl for your cage that way.