Horse Specifically Choosing To Roll In Poop (New Behavior)
So let me preface this by saying, thankfully this isn't my horse I'm about to discuss, but my friend's black Tennessee Walker gelding who is also boarded at the farm I keep my horse at. She's an experienced horsewoman but has never encountered this issue before with this horse or any other horse she's owned or worked with. I searched the forum and couldn't really find this issue specifically and google was limited mostly to dogs.
She has owned him for 12 years and he'll be 21 this June. He's got a very calm, laid back personality and he's usually a loner most of the the time, keeping on the outskirts of the herd, he's always been that way even though he buddied up with my horse.
Anyway, her horse has been on this farm since November 27th. He was kept in the same pasture my horse has been in which was only geldings, and the BO's recently moved him to the next pasture that has 5 other horses, 2 of which are mares to even the numbers of horses per pasture when a new boarder came. When 2 horses went out of town, they moved him back in with the geldings up until Saturday when they moved him back to the pasture with the 3 geldings and 2 mares. Yesterday after a long trail ride, when she put him back to pasture, he sniffed around until he found a spot that had fresh piles of poop and went down and rolled himself entirely in it, intentionally in the poop. Ick. He had a bath today, and I'm sure tomorrow when I go to check on him since she can't make it out to the farm, he'll be stinky all over again.
Any idea of what could be causing this, how to prevent it, or why he may all of a sudden be doing it? Is it a sign of submission or something? It's a gross, new development we'd like to nip in the bud if possible.