yup - that sounds about right unc. and the breeding rule fails more and more often as they discover more and more natural hybrids not all of which breed sterile offspring.- I believe natural hybrids have been found between cattle species, equines, felines, canines and many many bird species. and they can't always decide whether some animals are goats or sheep - I don't remember ever hearing about natural hybrids of goats with sheep or between species of the same - but bet they have occurred.