Maybe try looking it up on IMDb first? https://www.imdb.com/title/tt30519830/releaseinfo/
It’s still playing in film festivals. The first festival showing was in September last year.
I don’t pay much attention to film festivals (there are none near me, so not worth it), so I can’t really say how long it usually takes for a film to be made generally available, either in a wide theatrical release or streaming/home video (I’d guess about 6 months to a year for the most popular films?) but I’m pretty sure I’ve seen some that have taken a couple years or more. (Hopefully someone more astute can chime in here.)
Naked Lunch was my first thought, but, if not that, possibly Fear and Loathing in Las Vegas?
(I haven’t seen either in many years; I don’t recall anything about a talking horse, so am not very certain about either.)