For the wheat berries: In a large saucepan, combine the wheat berries, chicken broth, water, and salt. Bring to a boil over high heat. Reduce the heat to a simmer, cover the pot and cook until the wheat berries are tender, 60 to 70 minutes. Drain the wheat berries in a colander and set aside to cool, about 15 minutes. Transfer to a salad bowl.
For the dressing: In a medium bowl, whisk together the orange juice, olive oil, orange zest, agave nectar, mint leaves, salt, and pepper until smooth. Pour the dressing over the wheat berries and add the strawberries, goat cheese, and walnuts. Toss until all the ingredients are coated.
Cook's Note: To toast the walnuts, arrange in a single layer on a baking sheet. Bake in a preheated 350 degrees F oven for 6 to 8 minutes until lightly toasted. Cool completely before using.