Can scaly leg mites affect only a few chickens and not the others? I have 4 chickens right now. Two are 4 years old, two are only 1 1/2 years old. The two older hens are showing signs of scaly leg mites but the younger ones look fine. Is this possible? Would I treat all four, even though they don't all have symptoms? The other things I'm wondering is if none of them have it, and the older girls just have aging legs! But they do have the raised scales so I really think that it's mites.