What do you do with used chicken feed bags?
Here's what I've done.
They make excellent grocery bags. If you leave the diameter alone (as I do), then they'll be big grocery bags, but grocery bags are smaller than is completely useful anyway.
And the "fabric" is stiff enough that you can sew a box for your industrial size spools of thread.
Works pretty well.
I used a standard sewing machine, with regular needles and regular thread. I needed to be careful, particularly with hemming the top, but in the end, it worked just fine.
These are "quick & dirty" sewing, which is my specialty. I wouldn't want to sell these at the local farmer's market. But they hold groceries great. They make use of empty feed bags great. And they certainly are unique!