The form of deafness found in ACDs and bite issues cannot be tested for. They are a product of the mixed genes of the parents.
Here at Bullhead Kennels we realize that our breeding program is just one long experiment. We never blame one parent or the other for throwing an undesirable trait. Instead, we measure the severity of the issue and correct in a manner we find suitable.
If one bad gene is culled all the good ones attached to it are culled too.