Living behind bars or inside cage is one of the most weird and disgusting experience anyone could have, then whether they are humans or animals. And when they finally leave those bars, they normally gets astonished by seeing the world around them, because now this new world is not the one they left behind.
Now they realise what they were missing till now, and guess what would be their reaction after seeing this new world? I can just say priceless and heart touching.
Check some of the animals and their reaction after watching the outside world for the first time.