Position a rack in the center of the oven and preheat the oven to 500°F. Line a large baking dish with aluminum foil, and set it aside.

Rinse the hens well, inside and out, under cool running water. Pat them dry with paper towels.

Combine 4 tablespoons of the butter, the thyme, and the lemon zest in a small bowl and use a fork to blend well. Divide the mixture into 4 portions, and spread one portion under the skin covering the breast of each hen. Combine 1 teaspoon of the salt with 1/2 teaspoon of the black pepper, and season the cavities of the hens. Truss the hens, fold the wing tips back and tuck them under, and arrange the hens breast side up in the prepared baking dish.

Combine the lemon juice, honey, soy sauce, and the remaining 4 tablespoons butter in a small saucepan, and warm over low heat until heated through. Divide the honey mixture in half, and set aside one portion. Use some of the remaining portion to baste the tops of the hens well. Season the hens with the remaining 3 teaspoons salt and 1/2 teaspoon pepper.

Transfer the baking dish to the oven and cook, basting the hens with the honey mixture about every 5 minutes, until they are nicely browned, 20 to 25 minutes. If necessary, tent the hens with foil during the last few minutes of cooking to prevent over-browning.

When the hens reach an internal temperature of 165°F, remove the dish from the oven and let them rest for about 5 minutes. Discard the honey mixture used for basting. Use the reserved honey mixture to drizzle over the hens before serving.

Note: To check the temperature, insert an instant-read thermometer in the thickest part of the breast, avoiding any bones.