He certainly was not born deaf. I am afraid that most of our dogs hearing start to deteriorate from about 5 years of age. About forty five per cent are deaf by the age of ten years. Like us, as our dogs get older the eyes and hearing deteriorate. Neither we never fast a dog unless instructed by a vet.
Most people prefer to feed a dog once a day by the age of twelve months.
I always recommend two feeds a day, half in the morning and half in the evening. It is then easier for the dog to extract the right nutrients from the food. Most dogs are fed far in excess of their requirements. Most vets are recommending complete dried food. It is really detrimental to add any supplement to dry food.