Is the sale of a bird inside an open aviary (*burj*) valid?
Chapter on Selling the Musarrah (Animal with milk retained in udder)
Al-Mughni
Book of Sales
Primary text
If the bird is in an aviary, the ruling depends on whether the aviary is open or closed. If the aviary is open, the sale is invalid because if the bird is able to fly, delivery cannot be ensured. If the aviary is closed and the bird can be easily taken, the sale is valid. This aligns with the sound position that the difficulty in retrieving the bird from the aviary should be treated like the difficulty in retrieving a distant absent item, which is permissible if the usual effort does not render the sale invalid. This is the position of the majority of scholars.
Supporting text
The Qadi ruled that if taking the bird requires toil and difficulty, the sale is invalid due to the inability to deliver. This is the madhhab of Shafi'i, but it is countered by the case of a distant item requiring toil to retrieve, which is deemed valid because the effort and time delay are usually known. The correct view prioritizes that the variation in effort and time for retrieving a distant item is greater than that for retrieving a bird from an aviary, making the aviary case more deserving of validity if the distant item is valid.