Adjust the oven rack to the middle position and heat the oven to 450 degrees.
Line a rimmed baking sheet with foil, top with a wire rack, and spray the rack with vegetable oil.
Spray chicken with the vegetable oil spray.
Set the thinner, tapered breast pieces aside on plate, and roast the remaining chicken for 10 minutes.
Add the thinner breast pieces to the rack and roast the chicken for 10 minutes longer.