This reminds me of a time when I was a kid. We had a feeder set up in the pasture with crushed corn, salt, meal, and shredded hay. This worked great except it would get stuck from time to time and would not feed properly through the opening. This feeder would hold a lot of feed in the hopper so the cows would make a big mess around it. My job was to run my hand along the bottem of the slot to get loosen the stuck feed. One day I was down there doing my job, cows waiting for me to open the gate. On the way back through the mud I go stuck. Mud over the top of my rubber boots, suctioned in. All I could do was stand there cows staring at me and bawling for 2 hours. After my dad came home from work and composed himself from all the laughter he put a board across the muck for me to get some leverage on. After that he put some jig gravel around it. Jig gravel is whats left after mining iron ore. That worked great for several years. That feeder is long gone but I remember the exact spot to this day.