Preheat the oven to 375°F (190°C) and prepare the pie crust according to package instructions, blind baking for 10 minutes if a crispier bottom is desired.
In a skillet over medium heat, lightly sauté the chopped spinach until wilted. Remove from heat and thoroughly squeeze out any excess moisture to prevent a soggy quiche.
In a mixing bowl, whisk together the eggs, half-and-half, salt, black pepper, and chopped chives.
Spread the wilted spinach and crumbled feta cheese evenly across the bottom of the prepared pie crust.
Carefully pour the egg mixture over the spinach and feta, then sprinkle the shredded mozzarella cheese evenly over the top.
Bake for 35 to 45 minutes, or until the center is set and the top is lightly golden brown.
Remove from the oven and allow the quiche to rest for at least 10 minutes before slicing and serving.