Omega 3 and 6 fatty acids have a huge impact on your dog’s skin and hair/fur. A twice per week treat of 2 to 4 tinned sardines (depending on the size of the dog) can be hugely beneficial.
Alternatively, you can feed raw or cooked fish. Smaller fish have less heavy metals such as mercury, and are a safer option.
A good quality multivitamin or a fish oil supplement will also do the trick, particularly if your dog has a sensitive stomach.