Feed pellets and hay together??

I'm feeding Vitacraft Vitasmart Chinchilla food. My only other option locally is National Geographic Daily Diet Chinchilla food. Both are pellets with a tiny amount of hay mixed in. Does anyone have experience with either one or both of these foods? Are they okay?

For hay my options are: Kaytee Timothy Hay, All Living Things Natural Timothy Hay, National Geographic Nutritious Topping Timothy Hay, Vitacraft Timothy Sweet Grass Hay, and Oxbow Western Timothy Hay.

How do I feed the hay? Does it get mixed with her food? Do I just toss some in everday? Install a little hay feeder? Do you feed it daily in addtion to pellet food?

Thank you!!!