In 1981, an eagle-hacking project began at Pisgah National Forest in western North Carolina. This project was designed to raise golden eagles in a state of â€œpartial freedomâ€ so as to prepare them for eventual release into the wild. The birds come from an Eagle Propagation Project in St. Louis, Missouri, where they are artificially bred from injured or disabled eagles. The offspring are kept in hacking cages, large, open cages with stick nests, at nearby mountain balds. A bald is a grassy mountain-top area free of large vegetation. Birds are remotely fed so that they do not form human attachments and are released into the wild at eight weeks of age. It is believed that in three or four years, they will return to where they were raised to mate. Released birds are equipped with transmitters so that researchers can track them. The mortality rate of golden eagles in the wild is 60 percent. Of the eight birds released since the project began, five are most likely still alive.