I've had a group of them since winter of 2013/14, so this is the beginning of winter #4 with them, and you can't tell any of them from new.  Local place where I get them are around $240/240 today, about the same as I paid then.  Will never go back to anything else.  They hardly ever freeze to the ground, because they are so light, they are always shifting a little as the cattle eat through them.  The days of a small calf getting pinned under a hay ring?  Over.  They just squirm right out from under it.  I don't have the curved verticals, mine are just I believe three narrow rings toward the bottom and an upper ring, with 5 or 6 vertical tubes attaching them.  I abuse them with a loader and they just spring right back to round.  Thought I had a pic on my phone but can't find it at the moment.  Found a one on the net that looks almost identical.

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plastic_hay_ring.jpg (180KB - 177 downloads)