Preheat the oven to 450°F and position the oven rack to the top position. Line a large baking sheet with parchment paper and oil lightly.
Place the breadcrumbs in a large mixing bowl and pour in the milk. Stir and let stand for 5 minutes to allow the breadcrumbs to absorb the liquid.
Add the remaining ingredients including the shallot, garlic, red pepper flakes, ground chicken, cheese, and herbs. Use clean hands to mix it well until all of the ingredients are evenly distributed.
Use a large cookie scoop to form the meatball mixture into approximately 15, 2-ounce balls, packing them tightly. Wet your hands with water to prevent it from sticking.
Place the meatballs on the prepared baking sheet and drizzle lightly with olive oil. Bake for 15-18 minutes, until golden, and the internal temperature reaches 165°F.
To make the whipped feta, add all of the ingredients to a high-speed blender or food processor and blend until smooth, 2-3 minutes. Add more milk 1 Tablespoon at a time if it's too thick.