I live in surburban Canberra and have a TINY yard. I had 2 full sized chickens and they free ranged and made an awful mess. I had no garden left, they killed everything. Amazingly a fox got them - I wasn't locking them up and didn't realize that could happen.
I now have bantams - 4 of them. They are much lower impact. I have a house - like the wooden ones on eBay for around $150. They free range all day and I lock them up at night. They are not laying right now (grrrrrr) but Im expecting them to lay after winter. The eggs are half the size but just as yummy. I would really recommend them for small yards as they don't do much damage. Kids love them.