So I was going to make a shopping bag out of a feed bag, and then I started thinking about how my large can based feeder,and my plastic bucket based feeder were all about holding the feed in place to slide down a ramp. So the next time I was in home depot I picked up 51 cents worth of cull lumber and a couple of 2x4 cutoffs, and I made this. I'd say "Look at the new feeder I built!" but if I've learned anything from keeping bees, it's that everything I invent has been invented at least four times before. Regardless, here's what I call a "Bag Collar" feeder, because the base just acts as a collar and slide for the food. I'm the worst wood worker on earth and even I could build this, so I guess it can't be that hard. Note that the tolerances aren't too demanding - I sized this for a 30lb bag, and this is a 50lb bag in it. You can drop the feed bag into place, reach up and zip the string out. In reality it's just a square version of the round mason jar feeders everyone gets from the feed store which last about two weeks. But it's cheap. (cheep?). I don't bother cutting an angle on the slide - it isn't going to catch enough feed to matter, all that matters for this to work is that the bag mouth needs to be angled toward the slot. I'm pretty confident a better build of this would use a taller back piece but you go to war with the cull lumber you have. For fifty cents I can live with it.