Raising egg-laying chickens in the backyard is fun, self-sufficient and educational. Not only do you get fresh eggs out of the endeavor, you also gain some great insight in the poultry brain, get some laughter at their antics, and, if you choose, get some tasty dinners once your birds are past prime laying age.

The moment you put an animal in a cage or behind a fence, you are taking responsibility for the welfare of that animal. If you are a person of conscience, then you want to treat the animal well - possibly giving it a life better than if the animal were on its own in the wild. Does this imply that every person of conscience who has caged any animal has the arrogance to believe that they can improve upon nature's designs?
We can attempt to protect the animals from predators - this is easy to wrap our heads around. We can attempt to provide food that is better than what they would find in the wild. But wait .... we cannot seem to agree on what is best for humans to eat, let alone another species that does not speak our language. Some simple trial and error reveals what foods are preferred or result in "progress," but a lot of this information is being contested/disputed regularly.
The first domesticated chickens were plucked from the jungle. For thousands of years, chickens have been bred to survive non-jungle situations. But when they get loose they rarely survive anywhere on their own but in the jungle.