The Chi I bought in May, Kip, had an open fontanel. My Vet was really discouraging about it too. Kip was about 8 months old, and yes, it was a huge gap--as big as a Quarter. My Vet said it wasn't going to close and I had to be very careful with him. As it turned out, Kip went back to the breeder for other health issues. It is a common condition with Chi's. Just be aware of it and get on with enjoying your pup!