aviary
A large enclosed space where birds can live and fly.
An aviary is a large enclosure designed for keeping birds. Unlike a birdcage, which holds one or a few birds in a small space, an aviary is spacious enough for birds to actually fly around and move naturally. Picture a room-sized structure with mesh walls and a roof, filled with branches, perches, and maybe even small trees where birds can spread their wings.
Zoos often have walk-through aviaries where visitors can enter and watch colorful parrots, finches, or tropical birds flying overhead and hopping between branches. Some people build backyard aviaries to keep chickens, doves, or exotic birds. The Smithsonian National Zoo in Washington, D.C., has an enormous aviary where you can walk along paths while dozens of bird species fly freely around you.
An aviary gives birds something closer to their natural habitat than a cage ever could, with room to fly, socialize with other birds, and behave more like they would in the wild.