I purchased some RIR chicks from a local farmer. I was told they are 2 weeks old. I have other chicks (Australorps) that are 2.5 weeks. I got the Australorps at tractor supply, and they are half the size as the RIR's, and way less feathered. Does the RIR breed feather out quicker, and grow faster? Or are they possibly older than 2 weeks?