I have 4 rir 2 are 22 weeks 2 are 20 weeks. The two older ones stand about 19" tall. I have 2 buff orps that are 16 weeks old but are already almost as big as the rirs. The buffs free range in the back yard the rir cant because they are mean to the dogs. They have been fed the same but the buffs seem like they are big. The rir have a big run and gym so they have lots of room. Are my buffs big or are my rir small?