I posted before about using worn out conveyor belts as stall/aisle mats before.
My former barn owner got hers from the fruit packing house in my town, they would have otherwise been thrown out as they had no tread left on them.
If the ground you're putting them on shifts easily, like sand, as said before, mats probably aren't the best idea. But if you have a solid dirt base, they may work. Best of luck!
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