I think you're right tlaye, you notice it more on the lighter colored horses.
My buckskins seem to be more noticeable in hair loss then the others. My one buckskin starts to get his winter coat end of August; and he is the only one when it is cold and wet, that shivers. (at one event, one of the other geldings saw the extra tlc the buckskin got by shivering and commenced to shiver too - who says they aren't smart? That ole horse is as tough as they come, never saw him shiver or shake before or after that so you know it was a ploy.)
The red roan seems to be losing more white hairs then red ones right now too. We should try to keep track of the amount of hair that comes off in a brushing and compare the colors.
Also I've noticed that stallions seem to shed out abit faster then the others too.
"I believe that friends are quiet angels who lift us to our feet when our wings have trouble remembering how to fly."