I was given a bunch of Slessor poetry, but couldn't be bothered studying all of them, just Sleep and Country Towns, and their relations to change. I don't know what exactly you need, but this is what I'm working on.
Country Towns
Note the (sorry, I can't remember exactly) verses, 'houses of yellow wood', 'sign with 1896'... (somewhere in first stanza)
From these verses (and some others) we infer that country towns are obviously aging, thus changing.
But Slessor moves on to point out that Country Towns (note the 's' in Towns) don't like change, and are in fact, resisting it.
We know this from the image of a time warp which Slessor tries to create in our minds. In this time warp nothing seems to change, nothing seems to happen in this town -
The streets are empty,
there have been no more visiting circuses/troupes,
People sleep all day
Other people are passing near the town, but never disturb it (somewhere in 3rd stanza about dogs hearing something then going back to sleep)
Through Country towns, Slessor tries to tell us that change is inevitable. As the country town tries to resist change, we obviously notice some immutable aspects of nature such as aging. Slessor eludes to the inevitable surrender of country towns to globalisation - even though they try to resist change, the images of death (dead cicada skins, burnt pepper trees) taint the peaceful, serene image of the country town suggesting that something bad is going to happen...