@Arella Mae,
If she is raising her tail, carrying it higher at the top rather than having it lay flat, that is one of the signs of labor. If by stretching her leg, you mean her front leg and she's stomping at the ground or it looks like she's trying to move the ground around to make a "nest" then that is also a pretty good sign that she is trying to a) combat the pain and b) nest.
If either of these is also something you might see on any other day, then it may not mean anything. some horses carry their tails a bit all the time. Does she?
Regarding her milk production, didn't you say somewhere that Mac was still nursing from her? Or, was that lulu, who has been moved?