Chickens make great pets: free range eggs from happy, well-loved chickens are miles ahead of anything you'd get at a supermarket, they'll eat your kitchen scraps, they're relatively low maintenance if you set them up properly, and kids love them (to be friendly, it's best if you raise them from babies). It's a way to have a little piece of farm life in your backyard.
Different councils around the Melbourne area have different restrictions around how many chickens you can have, and how far your coop should be from your neighbour's property; most of them will have handouts and be really willing to help you. You can check them here. A healthy bird should produce up to six eggs per week, so two is a good number to start with and falls within most council guidelines. As well as talking to council, it's always good to get to know a local chicken expert as you'll eventually (as with any pet) come across a problem you're not sure how to manage.
You don't need a fancy hen house; an old kids' cubby house or a tent made out of recycled pallets will more than do the trick, just make sure they've got shelter from rain and sun. They'll also need a nesting box with a bed of shavings, a perch (they like to climb and flap around), something to drink out of (a bird feeder is great if you're going to be away for a few days), and some dirt or sand to scratch about in. In terms of food, you can buy pellets (and probably should if they're laying hens, as these mothers need to eat for two!) but they love vegetable scraps - they lose a lot of calcium when they lay, so make sure you crush up the eggshells and include it in their food (in the wild, birds will eat their own shells). It's always a good idea to ensure they have some kind of sturdy fencing around them (whether it's your property's fence or a new one), in case local cats or dogs get into your yard.
If you aren't sure what breed to get, ask around: they all have different qualities. Araucana hens lay eggs with green shells and tend to make wonderful pets if they're hand reared; ISA brown will produce a lot of eggs and have great temperaments.