J is for Jackaroo (Jillaroo), Jumbuck and Joey
Jackaroos (males) and Jillaroos (females) work in the outback on sheep and cattle stations, basically as station hands. A full description of their role can be found here.
Jumbuck is the name given to a sheep and immortalised in the song "Waltzing Matilda" (visit me on W-day for more on this).
Joey is a baby kangaroo. Joeys live in a pouch on their mother's belly.