I gave my dog an EXTREME Kong toy, the extra heavy duty ones and he was chewing away at it in his about ground kennel. I had nothing in the middle as I have no need in doing so he went to chewing right away. The tow was two days old and now it's in his intestines. My vet said if he starts throwing up then bring him in for surgery. Until then it's mineral oil and walks and digging thru all his droppings.