Grilled Poussins with Lemon Herb Butter

Stir together 1 stick softened butter, thyme, rosemary, zest, 1 teaspoon sea salt, and 3/4 teaspoon pepper in a bowl until combined well. Trim necks of poussins flush with bodies if necessary. Rinse poussins inside and out and pat dry. Discard any excess fat from opening of cavities, then sprinkle cavities with a total of 1 1/2 teaspoons sea salt and remaining 1/2 teaspoon pepper. Starting at cavity end of each bird, gently slide an index finger between skin and flesh of breasts and legs to loosen skin (be careful not to tear skin). Using a teaspoon measure or small spoon, slide 1 teaspoon herb butter under skin of each breast half and each drumstick (4 teaspoons per poussin), using your finger on outside of skin to push butter out of spoon. Put 1 lemon wedge and 3 thyme sprigs into cavity of each poussin, then tie legs together with kitchen string and tuck wing tips under body. Arrange in a large pan. Pat poussins dry, then brush with melted butter and sprinkle with remaining teaspoon salt.