Model horse hobbyists love initialism. OF, CM, SR, RR, LSQ, PSQ, NIB, MIB, OOAK, YCI, PSA, HR, PS--it's not unusual for an average MH$P ad to read like a cup of alphabet soup!
Fortunately, most of these abbreviations are pretty easy to decipher. Over the years there have only been a few that left me scratching my head with confusion. One of those was HSO. I can't tell you how long I struggled with that before someone clued me in to its meaning.
In case you're also wondering--this is an HSO.
|Not a horse|
|Even Emma knows that something ain't right!|
|Validator won't even look at him!|
|Gretchen enjoys some of the carpet ponies, July 2012|
|Only one of these horses still lives in Colorado|