Preheat the oven to 375°. Set a rack over a large rimmed baking sheet. Arrange the hens on the rack, leaving some of the marinade in the cavities. Roast for about 1 hour, or until an instant-read thermometer inserted in the inner thighs registers 165° and the juices run clear. Transfer the hens to a cutting board and let rest for 10 minutes before serving.