The "horn" on the Indian Horn Bill is actually a "casque." When the bird vocalizes their casque resonates. The casque is also for show.
The cardboard apparatus in the picture was built by the newest Tucson zookeeper. The male is pulling out the straw looking for worms. The tip of their large bills is more like needle nose pliers. They can pinch, but not crush. This allows them to pick the worms out of the straw.