In a mixing bowl, combine ground chicken, feta, parsley, red onion, garlic, oregano, salt, and pepper.
Form the mixture into patties, about 3/4 inch thick.
Heat olive oil in a grill pan or skillet over medium heat.
Cook the patties for about 5-6 minutes per side, or until the internal temperature reaches 165°F.
Remove the patties from the heat and let them rest for a few minutes before serving.
Serve on pita bread or burger buns with desired toppings.