My chickens go through about two bags of feed a week. That means I collect around a hundred bags a year. There's some recycling efforts available but I prefer to reuse when I can.
I've had an ongoing project converting an old dog house into a chicken coop. The roof is nearly flat so I didn't want to shingle it without any other protection. That's where the feed bags come in. They're water resistant so they should shed water well enough to work as an underlay.
My next project will be to try some feed bags for an archery target. Updates coming soon.