Its not your best choice of feed but it is better than others. If you are buying over the Internet I would suggest Tradition. I am down to only one chinchilla right now and I buy my feed from here:
http://www.ryersonchinchilla.com/arc_009.htm12 lbs of Tradition chinchilla feed boxed and shipped by us mail in Flat rate box. Will ship to anywhee in 48 states. 12 lbs with shipping included
Price $19.50
I keep it in the plastic bag, in the shipping box, in a cool, dry, dark closet. I close the bag tightly with a rubber band each time I feed. This should last about 3 months stored like this. You will still have feed but you can just toss that after 3 months and reorder. You will find this is actually cheaper than buying feed from your local pet store and you know it will be the best food for your chinchilla.