
The bird is free flying while hunting and not only is this great exercise, but makes it easier to judge whether this bird can make it out on its own. If the bird is successful at hunting it will be released shortly.
Falconry is also very time consuming and most rehabilitation facilities cannot put this kind of time into a bird.

ARC devotes many hours to each bird that we release, and we can only do it with your help!
Hacking
Hacking is a procedure where the bird is trained to come to a lure or a hack board feeding site once a day for food but is free to come and go as it wants. This allows the bird to get experience living in the wild while having a steady supply of food available until it learns to hunt on its own. After a few weeks of hacking, I will cut the feeding down to every two days and then down to every third day at which point most birds have gone off on their own. Hacking gives the bird exercise and experience that can never be gained in a flight cage. We usually use hacking with young birds that have no experience in the wild.

This is a lure, which is simply a piece of leather, usually weighted, with straps for tying on pieces of meat, used for training birds.

Here is a close-up photo of a radio tracking transmitter attached to a tail feather. The transmitter is used to track down birds that have taken off on their own. A special metal piece is crimped around the feather shaft and then the transmitter clips into it.
If you're interested in becoming a falconer, be sure to check out the time-intensive process in more depth, here.