All my down bags came with large "storage bags' which are large breathable cloth bags in which the bag fits loosely.

For some of my synthetic fiber bags, I just use good sized laundry bags. They are big and breathable, some are just mesh, and the bag just lies in it like in a loose pile without compression.

The idea is that the bag should take up a lot of volume as its "natural free state" during storage, and then when unstuffed from the stuff bag at your campsite, it will fluff up again to hight volume as in the "natural free state".

Simply put, get a great big bag to store the down articles in. Let them breathe too.

It is really simple. Hanging them does a good job of letting the bag occupy a lot of volume as its "natural free state". so it will fluff up to maximum volume when you get to your campsite.

Jim