What do you think about pigs in captivity? Do you set them free? I’ve seen them have fun In piles of mud.I see that @Doffy has answered that on the money.
I know people all over the world keep Australian parrots of various types in cages - the cockatiel a case in point - but if they ever saw them in the wild they may re-think that. These birds need large social groups to thrive and travel great distances in their natural state. To keep a bird like that in a cage or even "free" in an indoor setting (usually with wings clipped) is cruel.
Budgies are another great example. They are also parrots native to inland Australia. I've been lucky enough to see vast clouds of them in the outback.
Just last Easter I was sitting quietly alone in favourite spot in far NW NSW (very remote - nearest neighbour about 30KM away), when a small family group of about 50 budgies buzzed down and had a drink at the gilgai (watering hole) not twenty feet away. I sat perfectly still in the shade and watched them drink and noisily socialise. Colourful, clever, busy and beautiful.
Galahs live in large groups too and once they mate, like many birds they keep the same partner for life. In their case as long as 80 years. More than once I've seen the sad sight of one of a pair sitting at the side of its road-killed partner, gently nudging and cajoling the lifeless body.
Sulfur-crested cockatoos have a very large brain size/body mass ratio and are renowned for their intelligence and sense of fun. Watching a group of cockies swing upside down off the power lines, clowning around and playing chicken with passing cars, never gets boring. These are smart, problem-solving animals that should never be kept as pets for the pleasure of their human owner.
Doesn't matter if they are bred in captivity, the practice is barbaric.
As someone who has witnessed a lot of captive rabbits be set free only to see nothing left but some stomach and intestines left on the grass soon after I’d have to say once an animal had been kept in captivity that is the only life it really knows and letting it go is a death sentence and not being kind. It’s better to take it out back and be done with it than making it feel abandoned first. But that’s my opinion.
I also wonder why people are setting gold fish free all over the place because they grow “tired” of them… who can’t care for a gold fish.