cause the dogs in their natural environment know what they are lacking in their body and know where to find the substance which is lacking in their body to consume to compensate it. dogs in captivity rely on their owners to feed them, not having a chance to find what the lack in their diet. they can't tell their owners what they need so in the end, show symptoms of what is lacking in their diet which the owner provides.

Natural sunlight and excercise also contribute to healthy dogs.


Just my 2 cents ~