Hi there. So I am having an issue with the horses at my local barn. I am a stable hand there and have been working there for a year, but riding there for over 6 years, anyways; we have in one paddock 3 percheron crosses, and two Friesian sport horses. Then we have a paddock that is attached to this one, (Closed off) that has no horses in it. (We call it the "L" paddock.) These paddocks are made by 2 by 4 boards. Then attached to the L Paddock is another paddock, which holds two Tennessee walker mares (one who is lame), a warmblood mare, a Dutch Warmblood mare, and her yearling filly. So, one of the percheron x broke through and into the "L" paddock, and then broke into the mare's paddock. He cornered one of the Tennessee walkers (the lame one) who is 3 hands shorter than him, and put all his weight on her bum, and tore the flesh from her back with his teeth. The other 2 percheron x were also chasing and kicking / biting the other mares. All the horses are wounded, but otherwise fine, except for the Tennessee walker who is in rough shape.
Is this normal behavior? I have never seen such brutality in my years working with horses. Does anyone have any advice on how to fix this? Setting up stronger fencing isn't possible, as my boss says our fencing is fine. Any suggestions?