Go to your inventory and got to all.
Go to the very top and scroll over to the feather.
Hit it so that the heaviest item is at the top (multiple items don't show up so you may have to do some math, such as 25 x 1 pound items will show up as 1 pound not as 25lbs.)
Highlight your item and then press and hold LB (left bumper) you will exit out of the inventory screen and see the item hovering infront of you.
You may now walk around carrying that item as long as you have LB held down.
If you need to go through doors, take the item and then hit the door, then reselect it and go wherever you want.
If you have multiples of one item, you will carry them all and it will tell you how many items you have by looking at it.