Founder is Laminitis and though I never had one of my horses go through it, one of my best friend's horses did. I'm really hoping you called your vet for advice right away, but her mare was treated with anti-inflammatory meds and weeks of stall rest, then she was let out into the sandy pasture (easy on her feet). Unless the vet says to, I wouldn't force any of my horses to move around. It's very painful. Good luck and I hope she comes through it well.