Timing the saddle fitting
When should you measure your horse for his/her saddle – timing the fit
Because horses can change shape frequently, it is best to measure your horse when he or she is carrying most weight. The reason for this is that when your horse loses weight you can put a pad under the saddle to compensate for the volume that he or she has lost. If, however, you have measured your horse when he or she is underweight, there is no way that you can make the saddle fit him when weight is put on. It will be too tight. A skilful saddle fitter will recognize when the horse they are measuring is less than the weight they will be and will choose a saddle wide enough to accommodate them when they have gained their full weight. In the meantime they would put pads in the areas that haven't yet developed. However, this, at best, will always be a guess, because no one can be totally sure of the way in which their horse will change shape as they grow. So, if you are able to do it, let your horse achieve the greatest eventual weight and then measure him.