If you plan on keeping several parakeets, or a mixed flock of birds, an outdoor aviary may be ideal for you. An aviary gives the birds lots of space, and they will enjoy the benefit of fresh air and sunlight. An aviary can be a custom-made structure, free-standing or lean-to, or a converted outbuilding such as a shed.

An aviary gives parakeets lots of space and variety - and perches to snooze on, too!
Most aviaries are permanent homes for their owner’s birds, but some function as outdoor exercise areas or summerhouses only, with birds being confined to smaller cages during the colder winter months. If this is the arrangement you happen to have in mind, you will need to think of a way to get your birds in and out of their temporary lodgings. This will probably need to involve a net to catch the birds with.
Jane, 26 August 2019
This comment is addressing the comment made by David, Oct. 2018. Whenever I see someone wishing to breed more birds I cannot help but become saddened by this. Please try to understand that I truly mean no disrespect to you. The breeding of pets for whatever reason, spins off into so many misguided directions that all too often will lead to places like shelters, rescues or worse, euthanasia. If practical legislation that served the rights of animals, were enacted, maybe I wouldn't be sending this commentary, but none exists that I'm aware of. Responsible shelters & rescues are at least trying to take the surplus millions of animals & birds in their care be adopted to responsible people to give them a "forever" home. They do reasonable background work all in the interest of that animal to make sure it will not be dumped again. The sad reality David, is that many bred & pet shop animals will find themselves dumped at a shelter, which is why I'm urging you to separate your bird community (females in one cage, males the other). If you were doing this for income then I say please stop putting these birds to work for you. Ask yourself, can you honestly put time in to do background checks on the people you intend on selling these birds to? Can't you just love your birds for their own sake without breeding them?