If you happen to be around Danilovgrad on a Saturday, head out to this wonderful farm, established as a sanctuary for abused and neglected donkeys. They also produce (and sell) donkey milk, said to be incredibly therapeutic. It's a wonderful, non-exploitative place for animal lovers and families; the donkeys are used to small children. It's best to ring ahead before visiting, and though it's free to enter, visitors should take appropriate treats (apples, carrots, dry bread) for the star attractions.
You'll need a car to visit. It's 12km from Danilovgrad; follow the signposts to Gradina Martinićka.