They aren't necessarily made from feedsacks, but the fabrics look like they are from the 1930's. Feedsacks would have a coarser textures than regular cotton fabrics from that era.
This was intended to be an applique quilt. If I were you, I would learn how to hand applique. Later on you will want to find a good backing fabric, create oversized squares, applique these to the squares, and find either an authentic or repro 1930's fabric for the center circles.
Amazing find!!!