We did 14 days sheep hunting last season. The bulk of that much food gets to be somewhat ridiculous, but obviously it goes away pretty quickly.
A couple things on that note - Mountain House pro-paks are vacuum sealed, so there is no air in the package taking up space. If you don't want to pay for the pro-paks, you can take about 10 minutes and let the air out of your regular mountain house. Poke each pack with a needle below where the heat seal is on the pack, and above the ziplock. This is the part that you tear off to pour water in when you cook it, so it isn't going to leak there anyway. Squeeze the air out, and put a small piece of tape over it to re-seal. You can also roll the tops a bit so they pack tighter. My buddy trims all the sharp corners off of mountain house so they don't poke holes in the gallon ziplocks... I don't have that kind of patience.
I normally do the gallon ziplock per day, but it really isn't a big deal to have just a feed sack. So I have 14 Mtn Houses, a gallon ziplock of instant oatmeal, and a few quart ziplocks of trail mix, bars, etc all thrown in a stuff sack. I think this packs down somewhat better - fewer ziplocks = less trapped air.
