Black Jersey Giants have yellow feet. Australorps have whitish feet. But hatcheries can send chickens out with either- maybe it is genetic variation or just a mix-up.
Honestly I cannot tell them apart (BJGs and Australorps) - or couldn't when we had both at the same time from a hatchery unless I looked at the bottoms of their feet, so it is easy to be pleased with either in my opinion. They are nice chickens to have!