As a mare has an 'emply' system by the time she foals, yes I always give a small amount of their regular food with warm water added to make it mushy - she need moist food going through to make it easier for her, plus as much soft leafy hay as she wants. Dont forget the ivermectin wormer within 12 hours and she can have several small mushy feeds for the first day, plus grass, if she is used to it, as soon as the foal is steady on its feet - just an hour's outing will be fine for the first day. But if she is used to being out all day, then she will be fine out with baby for a hour or two for the first couple of days, she may get stressed if you try to keep her stabled!!