head size is nice to look at mate, but for digging foxes it dont matter, as the lads have said its the heart that counts. a mate of mine who keeps blacks has a dog with a huge powerfull head,a fine dog, great worker etc, but his sire is small and has a snipy head, the sire has a different attitude tho, he is rock hard and destroys his foxes. so cant see any reason why yours cant do the job, al the best with it