Where are you seeing that it is a mix of wild and farmed salmon? Their other fish is all wild. That is a question for the company to answer. Also, it is only a small part of the whole formula. As for the pea fiber, it is also low on the list, not making up much of the food. The company (the same one makes both Acana and Orijen) has careful sourcing, so I would not hesitate to trust their sources and feed any of their foods.
First time Chihuahua owner with many years of dog experience!