Preheat the oven to 425°F (220°C).
Prepare the Cornish hens by rinsing them under cold water and patting them dry with paper towels.
In a bowl, combine minced garlic, chopped rosemary, chopped thyme, lemon juice, lemon zest, and olive oil to create a herb mixture.
Rub the herb mixture evenly over the hens, inside and out, and season generously with salt and pepper.
Place the hens breast-side up in a roasting pan, and pour the chicken broth into the bottom of the pan.
Roast the hens in the oven for approximately 60-75 minutes, or until the internal temperature reaches 165°F (74°C).
Halfway through roasting, baste the hens with the pan juices to enhance flavor and moisture.
Once fully cooked, remove the hens from the oven and let them rest for 10-15 minutes before serving.