One more thing to mention...even though she is jumping and squealing when you try to touch her udder, I suggest you continue to do it even if against her wishes, because just in case you need to help get the foal to nurse, or even milk her to get colostrum or milk for baby afterwards, it is critically important that you are able to. Try tying her to a wall of some sort and just stay at her side, facing towards her tail end, speaking calmly to her and rubbing/touching her all over, and ever so slowly working your way towards her udder. Retreat a little further away each time she allows you to move forward. Just keep working your way toward her bag but just slowly with the forward/retreat rubbing, all the while speaking calmly and reassuringly to her.