In a large bowl, stir together Greek yogurt, lemon juice, dill, salt, and pepper. Add chicken, cucumber, tomatoes, olives, and feta. Stir to combine and top with fresh parsley.
For pita croutons:
Preheat oven to 375 degrees. Place pita pieces on a large baking sheet and drizzle with olive oil. Sprinkle salt and garlic powder over top and toss to combine. Bake for 8-10 minutes until starting to brown.