Adding Weight: Fat v. Muscle

This article helps clarify how to put weight on horses for more muscle or those who are underweight through feeding. The caveat for more muscle being this is in conjunction with an appropriate exercise program. You may bulk them up through feeding, but if conditioning is lacking, then performance will also lack due to inadequate development of muscle function through use. https://thehorse.com/166950/bulking-up-does-your-horse-need-to-gain-weight-muscle-or-both/