Arrived at a client's house and saw this...
I was very happy to see her mares were napping.
It took some experimenting and changes in herd dynamics for them to reach this point.
How often do you see your horse lie down?
Are they always in the same location?
Sleep at the same time of day?
How long do they sleep?
Over the years I've found a major contributor to many unwanted behavioral "issues" can stem from sleep deprivation in the horse.
Many fearful and anticipative horses cannot find a "safe" time/location to sleep, this can lead to a variety of dramatic and inconsistent behaviors that seem unaffected by training methods.
I believe it is one of the most underassessed, and overlooked aspects of the horse's health and well-being.
I've lost track of how many horses I've seen transition into amazing equine partners once their health issues were addressed.