A horse especially bred NOT to trot. Instead, are bred to have a very smoothe 4 beat gait that is 100% natural to them. They also come with a 'rocking chair' canter, and a flat walk. A flat walk is a 'working walk'. Much faster than your average Quarter horse walk.
^^ Gaited horses, besides Iceys and Saddlebreds, aren't supposed to trot. Some do at liberty, but that is a whole different story. They are allowed to. If they DO trot it is either a rider's error, confo issue, laziness, pain, bad saddle fit, etc. There are many reasons, but many people don't need to worry, because when they buy a gaited horse they 'test drive' them carefully. Some have their own gaiting styles so it is important to test them out and pay attention and think 'Can I handle this? Is this what I want?' What happens in the saddle gait-wise, is a very important thing in gaited breeds.
^^Ha ha! Well, hopefully the chiropractor will help.
Seems like there are several people on here with walkers who won't gait. My walker was kind of a "cheapie" and doesn't really have great breeding from the little I know about it. I really got her because of her temperament (I haven't ridden for like, 10 years), but so far, no trot. LoL, Iam lucky so far...but thanks to your posts, I will know to check saddle fit and alignment if/when she breaks into that bouncy trot. :)