Ostrich, apparently you can't read...as I never said they were totally free of any or all health problems. In fact, if you go back and read for a change you will see I mentioned they are not free of all health problems. However, what you will see is I stated PERFORMANCE TESTED WORKING DOGS (any breed...mutt or cross) have MUCH FEWER problems than non-performance SHOW dogs.
Of course, for you to know this (as well as to find your answer) you would have to read. And to do that, you would have to pull your head out of the sand.