I'LL answer your question: I have done it, with no ill effects whatsoever, and more than once. I have also ridden many a mare with foal at foot, also with no ill effects - what harm is supposed to happen? EXPERIENCE, rather than sentiment and fuzzy ideas, has led me to do these things - not all foals can be weaned at four months, but actually MOST well-grown, properly cared for ones can. I have bred approximately 200 foals in my lifetime (I am quite old, BTW), and officiated at many more births and weanings. Will you all please just leave this girl alone: she has done a great job, always had the best interests of her mare and filly at heart, and sought good, professional advice throughout. If you don't approve of weaning foals at 4 months, then don't do it. Plenty of professional, commercial breeders do so with no ill effects at all. Jeez!