We have a four-year-old warmblood (Hanoverian/Swedish) mare. She was in our barn for three months before we bought her. She was so amazingly gentle and loving. We've now owned her for eight months, during which time she gradually has become more and more aggressive.
When we first bought her, we moved her from a standard outdoor pipe stall (next to the lesson horses) to an oversized covered stall that was still was quite “open” to see other horses. She became very aggressive to the horse next to her and began pinning her ears when anyone entered her stall, especially if food was in her stall, and a lot of times when blanketing. We moved her to a standard-size indoor stall, and now she cannot see other horses except through the door bars. At first she seemed happier, but now she pins her ears, shows her teeth and lunges at any passing horse. She also has done this to people, including my daughter, a few times in recent weeks (minus the lunging). She is mean to other horses in the cross ties. We have her on 15cc of Regimate, Orchard, pellets, alfalfa, MiraCoat and electrolytes. Any suggestions? Thank you so much!
First, be sure to have your vet give her a thorough check-up. Sometimes horses will increase their aggression as a defense to keep others away. If she gets the “all clear” from the vet, we may be looking at some stall-bound issues. It sounds like she might have been stall-bound for quite a whilethat can certainly increase the likelihood of some of the behaviors you are seeing. I suggest increasing her time outside (paddock if possible; if not, hand walking), as well as other forms of enrichment. Try installing a treat-dispensing device in her stall, and maybe a brush mounted for her to scratch herself on.
Wendy, it’s also important to reward her for non-aggressive behavior. Walk back and forth in front of her stall until she relaxes. When she does, take her out for a nibble of grass or give her an enrichment device. While on the cross ties, walk another horse back and forth nearby, but not close enough for contact, until she relaxes. Reward with a scratch and a tasty treat.