My horse, Rainy, is turning five (March 15th) and I've never see her play. She doesn't run around in her pasture with the other mares, and if other horses try to bite/nibble at her halter or play fight, she just ignores them. She's completely unresponsive to the other mares- with me she'll follow me around, and nudge me and such, but with the mares in her pasture she just ignores them. Or just annoyed and pins her ears, kicks out at them, etc. She was put in our indoor arena with the gelding she's lived with for the majority of her life, and played just fine, running around and getting to know him again. So is it just her not liking mares? Or the two mares she's in with? Do your horses play or are they as unresponsive to play as Rainy?