Hi Faken. Glad to see someone from Canada. I don't really suggest the oxbow, as I've heard of issues with chins going off feed while on it from other pet owners who used it, or having tummy troubles/weight loss since they changed to a new formula in 2011. I do sell supplies in Canada, and the feed I sell is locally milled in BC. I don't know where you are located, but I do ship, as well as offer delivery in the area and I welcome customers to pick up locally too.
The diet I sell is Alderpark pellets, it is only $0.54 a lb, milled right here on the island, and always fresh. The diet is one that has been used privately by breeders and ranchers in BC, since the 1960's, when it was first formulated by a nutritionist named Dr Koch.
Dr Koch had studied both chinchillas in the wild and as well on fur ranches, back in the 60's, to determine what chinchillas need for a complete diet. While it is complete, you still need to feed hay for roughage, if you did decide to use it. I personally love the diet. I had used mazuri back in the late 90's and found while it is an okay diet for pet chinchillas; for breeding chinchillas, it left a lot to be desired. I've been using these pellets for a number of years now, and haven't had any issues. The chins tend to be rounder and have more muscle mass on their bodies with this diet.
My store link is: http://chinchillaparkplace.ca/chinstuffstore//
I don't know if Purina Rabbit show is available in Canada, and have never heard of it being used in Canada, but it is used often in the US and I have heard good things about it from the pet owners and breeders in the States.