It was milled on January 11th - it's good until maybe June-ish.
If your chins use about 2 lbs each every month, you'll only use maybe half of it. It's only a couple months old now, so it's perfectly fine...but in about three to four months you'll need to get fresh food. Like Jessica said...once you open it, it will be alright for about three months. Store it inside in a cool place...don't keep it in the garage or some place where it could get warm and spoil faster.
Don't freeze it, that can cause condensation and then mold to occur after you thaw it out. It's best to just keep the food in a cool, dry place like a pantry or in a closet. I keep the bags that I am storing for later use in a very cold air conditioned storage area. (But, I use all my food within three weeks of bringing it here, any open bag is used within about a day!)