pəˈrōsə̇s noun
( plural pero·ses -ōˌsēz)
Etymology: New Latin, from Greek pēros maimed + New Latin -osis — more at peromela
: a disorder of chicks, turkey poults, and young swans characterized by enlargement of the hock, twisted metatarsi, and slipped tendons and largely eliminable by additions of choline to the diet