Mix Italian dressing, olive oil, lemon juice, cider vinegar, crushed garlic, and crushed black peppercorns together in a bowl.

Place the mixture into a ziplock bag.

Add the chicken to the bag with the marinade, reserving some of the marinade for basting.

Seal the bag and place it in the refrigerator to marinate overnight.

Preheat grill to medium heat.

Grill the chicken, basting frequently with the reserved marinade, until the chicken is cooked through.

Prepare a cooler or large pot with hot water to warm it up.

Once the chicken is done grilling, empty the cooler.

Place the cooked chicken in the cooler with the lid on tight.

Let the chicken rest and rehydrate in the cooler for about an hour.