The scars on its body suggest that it has indeed had a difficult life. Perhaps it was mistreated or abused in the past. Perhaps it has been injured in an accident. Whatever the cause, the scars are a reminder of the pain and suffering that the horse has endured.

It is also interesting to note that the horse was nervous when it got closer to you. This suggests that it has learned to be wary of humans. Perhaps it has been mistreated by humans in the past. Perhaps it has seen other horses being mistreated by humans. Whatever the reason, its nervousness is a sign of the trauma that it has experienced.