1. Preheat the oven to 400°F (200°C).
2. In a large bowl, combine ground chicken, garlic, parsley, feta cheese, breadcrumbs, lemon zest, salt, and pepper. Mix well using your hands.
3. Shape the mixture into patties about half an inch thick and place them on a parchment-lined baking sheet.
4. Bake for 20 minutes or until golden brown, flipping halfway through.
5. For the sauce, mix Greek yogurt with diced cucumber, garlic powder, lemon juice, salt, and pepper until smooth.
6. Serve patties drizzled with tzatziki sauce alongside pita bread or salad.
