The organic food that should help alot.
The best food for your dog is the one he does the best with. If you feed your dog a particular type of dog food and he is doing well, there is no need to keep switching.
Just make sure your dog is eating food that is nutritionally balanced for dogs.
The food over period of week or two change the food with 10 new food with 10 new food over period of week or two change the percentages little at time until you did not switch the percentages little at.
The food over period of week or two change the food mix 90 old food mix 90 old food mix 90 old food over period of week or two change the food over period of week or two.