Would like to hear the pros and cons of stall mats.....I am in the Southern Sierra Mountains of California......have a Castlebrook Wood Barn.....love my barn......so do the horses......they are coming in just to pee!!!!
I loved stall mats. But they won't stop them from peeing in their stalls. Here's something else you can try.
I trained my horses to pee on a pile of soiled shavings I built at the end of each paddock, and reinforced them peeing there like I would paper train a puppy. When they'd pee in their stall when I wasn't around, I'd take a handful of soiled feed or shavings, scold them, hold it under their noise, point at the pee puddle, soak it up with shavings and carry the litter to the pee pile, and say "see, that's where pee goes, that's the good place" and when they'd look at it I'd praise the pee pile.
Now my cow-girl neighbors barn was 40 feet from mine, and she and her quarter horses would watch this, clap and laugh - she called it "Box Stall Training for Idiots".
I persisted. Any time they'd start to pee in their stalls I'd come unglued, would scream, wave rakes and yell. Chased outside by the crazy woman and desperate to pee, they'd pee on the pile and I'd give them an apple. It sunk in fast. Took me a week to get them going to the pile regularly. Soon after that, I realized they'd wait until I fed in the morning or evening to pee on that pile for an apple or goody. Every now and then they'd blow it, if it was really raining hard for example, but...
... what was the best part? My neighbor fussing at her horses "Why can't you pee outside like they do?". The next day her horses came flying out of the barn into their paddocks, snorting, tails in the air, and I heard
"Damnit you peed in here AGAIN!"