From: Mosquito Bite, Texas
Well, I don't know if I ever seen this happen to that degree before. Frequently, some of my troops won't make the battle, but I seem to get the vast majority involved unless I'm grossly over the divisional limit.
The numbers you see on the battle intro are the numbers in the province, not the battle. B2 is correct in that sometimes not all of them show up. Your situation is a little extreme, I suppose, but since it happened to you, it's must possible.
Maybe somebody with more detailed information can chime in; I suspect that there may be other factors in play. I wonder, for example, if initiative has something to do with who shows up to fight. Anybody out there know the answer?