My understanding is that the judge only ruled in this case that the birds were pets.
My interest in the definition of aviary is to dermine if it is specific, or so broad as to be essentially meaningless.
As an example, I have bees and there has been a pretty regular bit of confusion over hive styles and requirements. Not to belabor the issue, but it matters greatly in law whether a hive frame "shall" be, or "may" be removable for instance, and what "removable" means. Pretty picky, yes, but a strict reading allows a number of hive types other than what has been typically run in the US. And with this in mind, the state apiarist has determined that beekeepers have a good bit of latitude in what equipment they use. End of the confusion and no one needs to worry about their hives being removed for being the wrong type.
If there is a written definition, if is specific as to what constitutes an aviary, then it may be possible to work around those restrictions. If it specifies a permanent structure, then a moveable chicken tractor would otherwise be allowed. On the other hand, if it is very broad, and basically at the discretion of the inspector, then that would certainly seem to beg for a review of the regulation to eliminate uncertainty, and hopefully enhance the liberty of the citizens. If listed as an enclosure for housing birds, then that would include bird houses, and be unworkable.
The point is, that it must mean something specific and definable.
Anyway, I will look about a bit, and see what I can find.
Happy trails,
Keith