I have a yearling as well that began to exhibit physitis at 8 months. Switched feeds, analyzed hay, balanced diet on FeedXL. All vitamin and mineral amounts amounts are within 100%-200% RDI range. Mcals at 80%RDI. Protein at about 125% RDI. All ratios almost textbook. 4 months later, no resolution. Left knee is still painful. Her growth is average. Body score is 5. She’s not overweight or overly growing fast. Will she grow out of this? I planned on showing her, but her left knee is rounded on the inside. Her legs are still straight, thank goodness. I just can’t figure out where things went wrong. Unless it was just coming from a grass hay in the Eastern part of the US, to our hay here in the West.