I didn't know Australian Shepherds were chimeric. When I first saw a Catahoula I assumed they were part Australian Shepherd. Not only do they resemble them, but Catahoulas are used in herding cattle too.
"I didn't know Australian Shepherds were chimeric."
I don't know it for absolute certain, either. But, there are two causes for this that I am aware, which would be eye injury or chimerism, and I don't think every Australian Shepherd I've ever seen had an eye injury. Maybe there are other causes, but I'm not aware of them.