If you somehow stumbled upon this site looking for real-life pet adoptions, please take a gander here.
Merry Meet, Friend
"Robinhood Farm", unfortunately, is only a virtual stable created on the Sims 3 world, used as a roleplay setting for various characters including horses, humans, cats and dogs, to play out a story. This website has been created mostly so I can organize my own game, however, to inform other players in the Sims 3 horse community.
If you are interested in learning more or joining a community for such a purpose, I recommend E-Quest Sims.
(Note: "Robinhood Farm" is not an existing farm. This has been created for Sims 3. Any similarity to an actual farm, horse, or person is completely coincidence and not at all intended.)