Preheat the oven to 425°F (220°C). Line a baking sheet with parchment paper or lightly grease it.
In a medium mixing bowl, whisk the egg until smooth.
Add the ground chicken, breadcrumbs, grated Parmesan, minced garlic, chopped rosemary (or 1/2 tsp dried), oregano, crushed red pepper, sea salt, and black pepper to the bowl.
Mix gently but thoroughly with your hands or a spoon until the ingredients are evenly combined; avoid overworking the meat.
Lightly oil your hands and shape the mixture into 21 evenly sized meatballs, placing them on the prepared baking sheet about 1 inch apart.
Bake for 18–22 minutes, until the meatballs are golden and an instant-read thermometer inserted into the center reads 165°F (74°C).
Serve hot over pasta, with sauce, or as an appetizer with toothpicks.