the tornabene's had quite a few mastiffs titled ipo 1 , 2 and I believe one was ipo3 , they still may be active in that area , if so i'd imagine they got to be going on 20 yrs raising pups for sch/ipo , they sure struck me as knowing what they were doing , I think that girl knew dogs , and obviously how to raise pups to work , 0-8 weeks is a big deal ………. mastiffs are for the most part lacking in prey drive , they do not lack in fear/defensiveness , folks I've known did bitework with mastiffs used self defense to get them to bite because it's easy to do , even with an unsuitable dog , they were "hacks" ……... for every one Banuelos , Lucerno or Ritchie there are 100 hacks training dogs ………. a defensive dog that has little to no bite inhibition is in most situations a liability , probably why the breeders you talk to advise against it ….……… aside from biting , I've found any mastiff I've owned easy to train , I've yet to have one that wasn't ultra-food motivated , or eager to please ………