Pour ½ liter water into medium saucepan. Add 5 tablespoons kosher salt, 3-6 sprigs fresh herbs of choice, and 4 large cloves garlic to saucepan and quickly stir to incorporate.
Place saucepan on stovetop over high heat. Bring water to violent boil.
Once water boils violently, stir mixture until salt is completely dissolved, then move saucepan to cool burner and cover with lid. Let mixture stand, covered, 10 minutes.
Place 1 pound ice in large bowl. After brine mixture has stood 10 minutes, remove lid and carefully pour mixture into bowl over ice. Stir mixture gently until ice is completely melted.
When ice has melted, place 1 4-pound whole, uncooked chicken in large container. Carefully pour brine over chicken, making sure chicken is entirely submerged.
Let chicken rest in brine 2 to 3 hours at room temperature. Alternately, let chicken rest in brine 4 to 6 hours in refrigerator.
After chicken has brined for appropriate length of time, remove chicken from brine and drain well. Pat chicken completely dry with paper towels, then cook chicken as desired.