You got very, VERY lucky that your horse didn't get severely injured. I didn't bother reading the other responses, since all I wanted to do is share a story. My old horse judging coach had a horse before I knew her. This horse was her first horse, and whoever has had horses, the first horse always has a special place in your heart. She would leave the halter on all the time. I'm sure this went on for years. One night, her horse caught her halter on the fence when she was trying to reach a calf's food on the other side. She fought it until she strangled herself. My coach woke up to a phone call saying her horse was hanging dead from the fence by her halter. To this day my old coach vows to never let a horse have a halter on in the pasture. This is also the reason I never let my horses wear their's either.