I started noticing my then-4 yo mare's coat was getting the distinctive rough, lifted, fish-hook-shaped look to it that indicates a copper deficiency in the spring of 2024, and had also been fighting reoccurring (as in, monthly) abscesses in my yearling. While their diet was completely balanced based on my own knowledge and confirmed using Mad Barn's own calculator, I remembered my barn water was supplied from the house, was which filtered through my filtration system first because I had very hard water with a LOT of tannins (more than the company had seen in 60+ years, so it was an expensive system, yay me). Based on that, I suspected the filtration was throwing something off in their diet and added a zinc:copper supp as an experiment in early summer. I'm happy to report that not only ...