I too unroll and am getting tired of the waste. I have looked up how much waste one gets by unrolling and only found one study that said 20%, but other have suggested it can be as much as 40%. Don't know? It's nice to say just put out what they eat, and I try to but then the calves lie in it, pea in it and before you know you have a layer of hay on the grass that they won't eat - go figure?
Recent study in MI, as I recall, showed that the least waste, 3.5%, comes with using cone feeders, next best just rings 6+%, then it goes downhill from there with wagons, etc. I bought the cadillac of cone feeder ($725 each) and I love it, not the price, but this thing will last forever. ONly way to move it, because it is so heavy, is with a front loader. Now if you look at the flimsey plane rings at Tractor Supply they run around $220, so the extra was worth it to me.
If you do the numbers, 3.5% waste compared with say 20% of a $35 roll, it doesn't take long to pay it off.
Go with or make a cone feeder.