A horse

I'd been working most of the day, but we went for a run in the Pentlands this afternoon for a bit of a break. We passed a lady looking for a horse that (we think) had thrown her off. When we got to the top, someone had tied the horse to a gate. Amy reckoned it would feel guilty, but it didn't look too sheepish.

If you look closely you can see an "L" printed on its side. Do they come in different sizes?