We have been using Brewers yeast for nearly a year as a supplement for our horses and also give it to 6 underfed almost feral horses who live in fields down the road from us. There seems to be a difference in all of them. i.e. shiney coats, less rainscold, no mud fever... the ones down the road could get very lively when we arrived with buckets for them in the winter but they seemed much quieter and more laid back.(is that the brewers yeast?) I am beginning to think that it is a supplement that all horses would benefit from. The reason we started using it was to help our Cob Molly with her sweet itch. So far there is no sign of it this year. Although we are still using Nettex Itch stop (just in case). Molly has never needed a rug in the summer although we might have bought one if we hadn't discovered itch stop and now the Brewers Yeast.