HI, I'm a little confused here. I have been taking equine classes in cologe for the passed year and I have worked with a been around horses my hole life. For 6 years I worked for a friend of my families that owned a stallion out of Touchdown Kid. With this bloodline(Impressive's bloodline) he had to be tested to be registered. His HYPP is N/H. He has never had any type of "fit" or symptom from HYPP. I worked with and trained him from the time he was 2 1/2 and he was my favorite trail horse. While I was there this stallion was not bred to any mare, paint or quarter horse, that was N/H. They were either N/N or had NO Impressive blood. Of the foals that where registered by the farm and not registered by new owners there way only one that came back as N/H. Also in the classes I am taking we had a section(a very long one) on HYPP. I was taught that there is a 25% chace of getting an N/H foal and 75% chance of getting a N/N foal if one parent is N/H and one is N/N. So I guess I just don't understand where the 50/50 is coming from if the mare is N/H and is not bred to H/H or N/H stallions. I am neither for nor against N/N or N/H HYPP horses and yes I have seen and delt with some very bad things because of it and the horses where H/H. One was an H/H paint mare that was that was tested after she was purchest and had already bred to an N/H stud before she was purchest as APHA didn't require HYPP testing. She didn't make it threw foaling, the foal only mad it a week. So I am against H/H horses and the breeding to get H/H horses.