1) Set the sack firmly on the ground with the stitched end containing the tag, facing up. Look closely at the stitching at the top of the feed sack. One side of the stitching will be a flat single running stitch, while the other side will have a knotty or looped appearance.

2) Stand facing the feed bag with the looped or knotted stitched side of the bag facing you and the single running stitched side facing away.

3) Grasp the corner of the bag to your left and with a scissors or knife cut off the chain of stitches that extends past the edge of the bag.

4) With the point of a knife, scissors or your fingers,on the just cut end, pull the string on the last stitch of the flat running side, until it comes out through the stitch hole.

5) Grasp the end of the flat running-stitched string in your left hand and the loopy string in your right. Pull the strings away from each other. The stitching on the bag should unravel across the top, leaving you with an open feed sack.

Video below showing the complete process described above