Tell them she has lost foals before (still haven't read you diaries sorry) They will give free sound advice if they are anything like ours. I was worried too about Vit., but didn't want to poke me nose in. Best Wishes I hope it all works out keep us posted. I only have instincts, (which do not fail me) no real knowledge so didn't feel qualified to say. That is why I asked about stallion. If they are covered in confinment, ai etc you know when foal is due, if stallion runs out with herd its all over the place. Very stressful time for you. Keep calm and ring vet