Spray some nonstick cooking spray inside the Crock Pot and place the turkey inside.
In a small or medium bowl, add the butter, salt, pepper, onion, garlic, thyme, parsley, and rosemary and mix well.
Pat the turkey dry with a paper towel.
Take a spoon and slide it under the skin of the turkey breast and spread some of the butter underneath.
Spread the rest of the butter on top of the turkey skin.
Pour the chicken broth into the Crock Pot.
Place the lid on top and cook on low heat for 8 to 10 hours or until the thermometer reaches 180F in the thigh and 170F in the thickest part of the breast.
Once the turkey is done cooking, carefully pour out some of the liquid (save it if you're making a gravy recipe).
Take the crock out of the Crock Pot and place it under the broiler in your oven for a few minutes to get the skin crispy. (Make sure your Crock Pot crock is oven-safe. And make sure you remove any plastic holding the turkey legs together before placing it in the oven).