answer:A Kong cannot be too big. It is important it is big enough, though. The pup can start using a large Kong right away. The question is, rather, up to what age can this puppy use Frodo’s Kongs safely… Will the pup be bigger than Frodo when grown? What size are Frodo’s Kongs? Related: The Kong company says to make sure the rubber is still firm. In my case, it took six years of regular use and cycles in the dishwasher before I noticed wear. Just something to pass along. Also, before leaving a dog alone with any toy, the owners should be reasonably sure of their dog’s play-style. If this new dog is dead set on tossing the Kong up and having it land on its head, it needs to be supervised. Hugs.