Hi Tyler- Why not feed her both? Both Orijen and Acana are very high quality foods and offer a lot of different formulas to use in a rotational diet. Variety is very healthy for dogs, just like it is for humans.
If she needs to gain weight I would feed her the recommended amount for her weight or maybe just a little bit more and then add something like coconut oil to her food. Coconut oil is very high in calories, but also offers great health benefits for humans as well as dogs and cats. Once she is at an ideal weight you can cut back on the coconut oil.
