@drillersmum85,
I would listen to the vet. Two things to think about...
Dogs are not designed to live in nature. They were bred by humans to eat what humans give them. There are very few dogs that could survive on their own as hunters, stray dogs stay near humans and survive as scavengers
Human food, even raw food, is not what predators eat in the wild. Chicken you buy in the store is mass produced and likely to have bacteria that a natural predator would not have to deal with.
Dogs do fine with dog food.