Prepare the brine solution: In a large bowl or pot, combine 4 cups of water with ⅓ cup of kosher salt and ⅓ cup of brown sugar. Stir until the salt and sugar are dissolved completely.
Add the flavoring ingredients: Stir in 2 tablespoons of black peppercorns, 2 bay leaves, 1 tablespoon of garlic powder, 1 tablespoon of onion powder, and optionally, 1 tablespoon of dried thyme and 1 tablespoon of apple cider vinegar.
Submerge the chicken: Place the whole chicken in the brine mixture. Ensure the chicken is fully submerged. If needed, you can place a weight on top (such as a plate) to keep the chicken in the brine.
Refrigerate and brine: Cover the pot or bowl with plastic wrap or a lid. Place it in the refrigerator and let the chicken brine for at least 1 hour, but you can go up to 4 hours for deeper flavor.
Prepare for cooking: After the chicken has brined, remove it from the brine solution and pat it dry with paper towels. Discard the brine. The chicken is now ready for roasting, grilling, or frying.
Cook the chicken: Depending on your preference, roast, grill, or fry the chicken as usual. For roasting, preheat the oven to 375°F (190°C) and roast for about 1 hour, or until the internal temperature reaches 165°F (74°C). For grilling or frying, adjust the cooking times accordingly.