Preheat the oven to 400°F. Line a rimmed baking sheet with aluminum foil.

For the sauce, combine cranberries, sugar, orange zest, orange juice and mandarin orange segments in a saucepan over medium-high heat, stir to blend.

Bring to a boil.

Cover the saucepan and decrease the heat to low, simmer, stirring frequently, until berries have broken open and released their juices, about 8 to 10 minutes.

Add port, stir, and cook for 2 minute more.

Divide sauce.

Using a mesh strainer, strain half of the sauce into a small saucepan by pressing on the solids with the back of a spoon to create a glaze.

Place remaining sauce in a separate serving bowl, set aside.

For the hen, rinse hen halves and pat dry with paper towels.

Sprinkle with salt and pepper. Place hen halves, skin side up, on the prepared baking sheet.

Brush about 2 tablespoons of the glaze over each hen half, coating generously.

Roast hen halves until golden and their juices run clear, about 25 minutes.

Pour pan juices into reserved glaze mixture and bring to a boil.

Reduce heat and simmer to thicken slightly and blend flavors, about 3 minutes.

Transfer hen halves to plates. Spoon remaining glaze on top and serve with sauce.