So our first "Q and A" answer for Casey: Her question was "Is it difficult to re-train a horse to neck rain?"
It's no different than teaching it to any other breed of horse, but for some reason, a lot of people think a "race horse" is wired differently from other horses.
Teaching neck reining is a natural progression that can be broken down into simple elements, as any other skill a horse learns. A Thoroughbred coming out of race training is accustomed to direct rein cues from a snaffle bit, but is typically weak on responding to leg cues, as the shortened leg position of an exercise rider or jockey inhibits the use of leg as an aid. The horse has to learn to work off leg pressure, combined with direct rein, before he can move on to understanding rein pressure across his neck.
One problem we avoid is trying to retrain an OTTB that's in race fit condition. In our program, we try to turn a horse fresh off the track out for several months. This also helps freshen his attitude and get over any body soreness or hoof issues. It's difficult to train any horse that is on the muscle, as there is a window of time in any training session when the horse just tired enough to relax and learn, but not so tired his mind shuts down and he becomes resistant.
Hope this helps and keep in mind, patience goes a long way toward obtaining results!