Orijen and Acana are great foods, much better than Royal Canin. Make sure the food says “puppy” or “all life stages” on it. As for how to transition, the answer is very slowly, over at least a week, longer if he needs it. Also, diet rotation is a good idea, because no food is perfect. Here is some more info about that: /frequently-asked-questions/diet-rotation-for-dogs/
Remember to slowly transition to each new food. 😀
You should probably keep using puppy foods (you can still rotate, as long as they are all puppy foods) until she is about 6 months old, and then you can transition to adult food.
