Pretty sure that would be doing something like desaturate, lighten, add details of dapples, Vetta. But I also suck at art and haven't done any in over a year, so not sure.
I probably don't need that fast of internet, but my excuse is I need it for work. Really, I'm impatient and hate waiting for my games to download lololol
Grow > Upgrades And More, then select the respective category [barns, pastures, etc.]. Your barn/pasture must be empty in order to sell it back to the game. If your barn/pasture is empty, there will be an option to sell it back on that page.