Haha, you do that too Faceman? I know when Lena's colt stopped rumbling around in there I constantly walked the pasture. Though, obviously didn't lose it to early.
With Lena, she was obviously pregnant, even at 5 months. When I first got her she looked to be as well, but that was due to worms and other issues. I guess it really depends on the mare. More seasoned broodmares probably show earlier then mares that are barren half the time and even more so to maiden mares.