Some feed sacks have that issue of seperating,i think when they were made the layers r not bonded correctly.I always pre wash.I make mine to the best of my ability,i can not guarantee how long they will last,due to how they r cared for,i had one myself for over a year,then it started to seperate.
Thanks for the great reply. I guess I just got unlucky. Though I did read an advertisement for recycled feed bag totes, and it said the bags could not be washed, so ... I'm going to have to do a bit more thinking on this!