@TeaLovingDave The various empty cages are mainly to be found on the right-hand side of the zoo, and in truth I think that if there isn't going to be any use for them then the zoo should make an effort to remove the eyesores. A rough location for this particular cage is near the 'Heron House', on the trail past the Persian Fallow Deer and towards the macropod exhibits.
@snowleopard I rather prefer they keep old exhibits like this, theirs a certain charm I appreciate and they can still be useful provided appropriate species are exhibited.