Call a vet ASAP!!!! If a vet can't/won't come out, throw the baby into the cab of your truck and take it there!
Are you SURE it hasn't gotten up at all? Have you been watching it constantly? Babies do lay down and sleep a lot. If you're sure it hasn't fed, it is probably greatly dehydrated. Also, it is missing out on the colostrum. Try milking the mare and giving the baby a bottle or syringe it in. This is an emergency and something needs to be done NOW!!!! Good luck and keep us posted.
Phew... We took her to the vet, the problem was that she had Meconium or something like that. (The Foal) But she's fine now! Thank you guys so much for telling me what to to. I did drive her to the vet ASAP. She had surgery and is fine now.. Thank-you sooooo much, the filly might not even be alive by now if you didn't help me!