Apparently a manifestation of a Santeria ritual.
Miami-Dade College anthropology professor Mercedes Cros Sandoval explained, "This is a magical ritual of Cuban origin, probably, with the name 'Sarabanda,' which is a deity from the Congo area that was probably used to affect the relationship of these three young people. To me it is alien, the idea of casting your sins on innocent animals," said Sheehan.Alien, yes, but not inexplicable when one remembers the Western tradition of "sin-eating" and its relationship to Christianity.
More details here, via Nothing to do with Arbroath.
p.s. - I rather suspect when they named the chicken, the rescuers intended it to be spelled "trouper" rather than "trooper."