I have never heard about it being normal in walkers. My cousin has a walker she almost sold because of the loud nasally noises because all the other walker people she rode with insisted she can't handle trails and work. Never heard a one of them do it. She will go go go but the noise isn't after hard work but anytime. She ended up buying a second one who does not do it. Two vets have checked her out. We have thought her face looks a little off and she may have hit a fence or something when she was younger(no real scarring) obstructing her airway. But they kinda poo pooed that idea. There was an article recently in one of the horse magazines and it kind of sounded like it. Really worried me but I can't remember what it was called. Something about the cartilage supporting the airways wears down or paralyzes and the horse will suffocate eventually. The signs are the nassally noises. The vets told her to ignore it and some horses just do it. But I would have her checked out just to be careful. Funny thing with my cousins horse was whenever a vet comes out no matter how hard you work her she won't make the noise! If your looking at walkers these are the people my cousin goes riding with sometimes http://www.twhorses.com/ I think theres are taller than her about 15 hand horses. Not that there are not a million walkers out there though!