25% of you mare's diet is untested hay (unsoaked) and from what I understand from your post your gelding is fed the same hay (soaked) and it is at least 50% of his diet and soon to be 100% (?). I don't understand what you mean when you say you will analyze his hay and get him a custom supplement when the time comes? What time is that? Addressing the iron overload issues starts with a hay analysis. I, also, think it would be prudent to know what the 5#'s of hay is contributing to you mare's diet or if you could feed her daily ration in this now tested hay.
