This is half a roasted poussin from Griggstown Quail Farm Market. I buy them pre-marinated in herbs (there’s also a soy-ginger version), and they are reliably tender and juicy. I often keep one in my freezer, and it’s enough for 2 servings.
I roast the poussin for about an hour (to 165°) on a bed of split fingerling potatoes, or rough-chopped carrot/onion/celery, or, in this case, leftover stuffing.
The young chicken has been spatchcocked, which means the backbone was cut out, and the bird flattened. This ensures even cooking. For a nice pictorial of this, visit this site.
But, here, Griggstown has done it for us, and each time I enjoy one, I wonder why I don’t have it more often.
NJ SPICE 
The soy-ginger sounds tasty, and it seems so easy to make.
Everything they sell is so reliably delicious. Love their duck breasts too.