Preheat the oven to 375 degrees . In a large skillet, heat 1 teaspoon olive oil over medium-high heat. Add the sausage and oregano and cook, breaking up the sausage, until just browned, about 5 minutes. Drain and let cool.
Grease a 9-inch pie pan with the remaining 1/2 teaspoon olive oil. Place 1 piece biscuit dough into a large resealable plastic bag and, using a rolling pin, roll into a 1/8-inch-thick disk. Remove the dough from the bag and transfer to the prepared pie pan. Repeat with the remaining dough pieces, pinching the pieces together in the pan to form a crust.
In a large bowl, combine the cooked sausage, onion, feta and olives; spread evenly over the crust. In a medium bowl, beat the eggs, egg yolks, milk and 1/8 teaspoon each salt and pepper. Pour the egg mixture over the sausage mixture and bake until set, about 25 minutes. Let cool for 10 minutes before serving.