Poussin is the name given to Cornish game hens in Britain and France, and it refers to a young chicken less than 1 month old. Often referred to as rock Cornish game hens in the United States, these birds are usually in the 1- to 2-pound range, making them convenient to cook for a small group or individual, while shortening the cooking time significantly over a larger bird.
Preheat the oven to 425 degrees Fahrenheit. Meanwhile, rinse the poussin with cold water from the tap inside and out and pat it dry with clean paper towels.
Place the poussin in a baking dish and brush it all over with extra virgin olive oil. Sprinkle sea salt or kosher salt and freshly ground black pepper over the outside of the bird to taste.
Put the baking dish in the oven on the center rack. Bake the poussin for 40 minutes without opening the oven door.
Check the internal temperature of the poussin with in instant-read thermometer in the thigh portion of the bird. When the meat is fully cooked, the internal temperature will be 165 degrees Fahrenheit.
Remove the poussin from the oven and loosely cover it with aluminum foil. Allow the poussin to rest for 10 to 15 minutes before slicing it or serving it.