What we found worked the best for us were troughs, the ones with aluminum frames. Lots of cows can get up to them at once, the bulls don't mess with them and they are real easy to move. Mr. FH ties a rope onto them and pulls them into the next pasture. It won't help mineral that turns rock hard when it gets wet, but that wasn't a problem with the mineral we fed.

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Vigortone makes the BEST, (yes, they are the best!!) poly feeders on the market. They have a bearing at the bottom and they last forever. Our customers that have old ones, call for more, and when they get them, they are amazed that they are even better built than their old ones! We didn't use them because they only hold a couple of bags of mineral at a time. You might get 3 bags in one, but that mineral never gets wet, as the poly feeders turn with the wind. They really are the best on the market of that style.
We also have available Dura-Bull feeders that set on the ground. They are divided into sections so you can put mineral in each section. They are available with a cover. We've never sold one, but ranchers in ND and SD use them. We worry that with the cover, a calf won't stick his nose under the cover and get to the mineral. It's my belief that the calves eat as much mineral as the cows during the spring/summer and it's to the producers advantage to have the calves be able to access the mineral. The mineral enhances rumen function and digestibility so the calves can eat more grass and therefore, gain more weight. The sales people in ND and SD sell a lot of the Dura Bull feeders and say the calves will pick up the cover. I can't testify to that one way or the other, as I've never seen one work, but as many as they sell, they must be fine.
Most of our customers use the turned-tire feeders set on wood. The bulls can sure tip them over, but they are very cost effective and last a long time.
The FFA sells makes and sells them here. I think many FFA chapters make and sell them.
Hope this helps!