Preheat the oven to 400°F (200°C). Line a baking sheet with parchment paper.
In a large bowl, combine the ground chicken, breadcrumbs, Parmesan cheese, parsley, red onion, garlic, egg, oregano, salt, black pepper, and red pepper flakes. Mix until well combined.
Form the mixture into small meatballs, about 1 inch in diameter, and place them on the prepared baking sheet.
Bake the meatballs in the preheated oven for 20-25 minutes, or until cooked through and golden brown.
While the meatballs are baking, bring the chicken broth to a boil in a medium saucepan. Add the orzo and cook according to package instructions until al dente, about 8-10 minutes. Drain and set aside.
In the same saucepan, add the olive oil, lemon juice, and lemon zest. Stir to combine, then add the cooked orzo and toss to coat.
Once the meatballs are done, serve them over the lemon orzo and sprinkle with crumbled feta cheese and additional parsley for garnish.