I have two Flemish's. One being fed about 1 cup and a half to 2 cups from a 50lb. (also being fed unlimited hay and some dsily greens) will go through roughly half of it in two months, which is about when you need to get a fresh new bag from what the experts tell me. Now at the time I'd have to throw out the rest of the food which seemed like such a waste and a great argument to get a second Flemish . Of course this is the first time I'm hearing it can be refrigerated so...
as blue eyes said, freezing's a no-no. the best thing to do is to transfer some of it to gallon ziplock bags, push as much of the air as you can out of them and store them in the fridge
when I take mine out of the fridge, I just pour some into the kind of tupperware container meant for cereal, then close the bag back up if it's not empty and stick it back in the fridge.