OK, so a few things.
New Hampshires are really hard to find and the quality in South Australia aren't that great. There may be a few exceptions, but you could go months and not see any advertised. You might want to try Rhode Island Reds as an alternative.
Welsummers are easier to come by and better quality overall. My personal experience with Welsummer hens was that they were fairly drab and uninteresting, with no real personality. But that's just my experience.
Rhode Island Reds, Australorps, Langshans and Sussex have been some of my favourite breeds over the years. Less worthwhile for various reasons including being flighty and noisy are Barnevelders and Leghorns. But other people may have had different experiences, and bloodlines do vary within breeds.
Also ducks are worth a shot and can be a lot of fun. Indian Runners are usually great egg layers but can be a bit nervous. Pekin ducks, if you can find any, are larger docile ducks that can also lay very large eggs. Both these breeds are flightless, so they won’t fly away. Personally I don’t find ducks all that noisy and at least they don’t crow.
When looking for birds, poultry clubs can be a place to start. Try the South Australian Poultry Association, The Lobethal Poultry Club or the Strathalbyn and Districts Poultry Club. There are a few clubs in Adelaide and also one in Murray Bridge.
Gumtree is one possible place to find poultry and there is a lot on there, BUT BUYER BEWARE! People say all sorts of things on Gumtree that are often simply not true, so it really pays to do your homework. Often people use images off the internet instead of their actual birds. Right click on the images and select "Search Google for this image". If the results come back with no links and just "Best guess for this image: chicken" or similar then it's legitimate. If it comes back with all sorts of links from all over the internet, or even just one then it's not legitimate (unless it comes from the seller’s website). Now some honest sellers will still use an image off the internet for simplicity and to save time taking their own photo but they should display that honesty by mentioning in the ad that the pictures are from the internet as an example only. Also, a lot of people make all sorts of extraordinary claims on Gumtree about their birds that range from outright lies to just innocent misguided misinformation.
Finally, quarantine and disease risk are quite real and can be quite devastating. There is no easy answer to this. A sensible breeder and seller won't allow poultry people on to their property for fear of tracking in potential disease on their boots/shoes and clothing. Assessing a seller for their level of biosecurity is very hard therefore. If they let you (and anyone else) on to their property to view their rearing arrangements then you, they and everyone else have potentially distributed all of the collective diseases in all of their yards to each other (many serious poultry diseases can be retained and transmitted via soil, feathers, dust and faeces). In the real world, however, we all go places where there are poultry (the pet shop or fodder store, poultry clubs and shows etc.) but it is worth reserving special footwear and different clothing when going out to our own poultry.
Also when bringing chickens back from a show or new chickens into our yards we really should quarantine them for at least two weeks to be sure they are clear of disease. This means keeping them in a pen or area that is separated by distance from the rest of our birds and where other poultry are not routinely kept. Of course many people find all of this way too much and so don’t bother.
Obtaining vaccinated birds is a good idea if all your birds are vaccinated but if some are not then the ones that are can still carry the disease vectors and expose the ones that are not. Also, many breeders of pure breed and show poultry do not vaccinate because it can be difficult to do for the small-scale breeder. Therefore your choices become very limited if you only buy vaccinated birds. The other argument is that unvaccinated flocks build up a naturally disease resistant population over many generations of natural immunity. Also, wise breeders will only breed from hens, not pullets, because hens have proven they have survived possible exposure to disease longer and remained healthy, and also for some diseases hens pass on a very small percentage of disease vectors compared to pullets, thus helping to arrest the disease transmission cycle.
It is always a risk bringing new birds into your existing flock, but when you need to you just have to risk it. Perhaps quizzing the seller on the health of their flock and the biosecurity measures they use is one way to flush out a dodgy seller. Just remember that there are some extremely serious and devastating poultry diseases around and once some of them visit your flock they can stick around and haunt you for a long time.
_________________The Home Flockhttp://thehomeflock.webs.com/Sustainable poultry keeping and breeding for every space and place.