What types of enrichment do you provide the monkeys?

We have a combination of natural and artificial vegetation throughout the monkey sanctuary. Our goal is to simulate the life the monkeys would be living in the wild. They travel and forage as a means for diet and enrichment.
The monkeys have large enclosures and travel between their indoor and outdoor enclosures via walkways. We place treats such as sunflower seeds and raisins on the ground in the straw bedding to stimulate foraging behavior. They receive two forms of enrichment daily which is planned out by the Primatologist. Enrichment includes food puzzles, magazines with honey and seeds, stuffed kong toys, and playing music or movies. We also take pride in feeding the monkeys throughout the day with fruits and vegetables and also their monkey chow which contains the vitamins and proteins they need.
We coordinate volunteer days to plant vegetation for them and incorporate branches into their enclosures. Although it could cost hundreds of thousands of dollars, we would one day love to see even bigger enclosures constructed around the existing trees on the property.
Monkeys displaying “presenting” behaviors to staff can be groomed safely by using a backscratcher. The  monkeys get to know and trust the staff as one of the primates in the troop. Even though the monkeys are housed in their own primate troops, they are keenly aware of each other in the monkey building and are also enriched by the sights and sounds of each other.