Nicker, I don't have the info at my mental fingertips but Vit A (?) is supposed to be something that is really good for skin issues and is easily fixed with an injection or supplements. I also think Omega 3s are good for skin and immune system disorders. On the question of a TWH who may have heaves, I would not go there without doing a lot of research and having a vet's report. It for sure may require special handling (dust-free hay, not being stalled, and meds). Plus, you might never be able to use the horse to the fullest.