ok, interesting thing happened today, so my slan was being babysat buy his ~TG things were peachy, untill they were charged by two stegadons, it hurt, lots, and i ended up loosing all but 4 of the TG, now, the unit was originally 5 wide, so there was one less rank than there should have been, should the slan have moved forwards then? making the unit effectivly 6 wide? stayed where he was? assimg he stayed, would he have moved forward when there were 3 TG left? to keep them 5 wide? the only bit i can find is an almost fluffy piece about the slan ranking up behind the TG thoughts?
This is covered on the army rules page in the army book, it talks about both krox and slann mixed units. In summary, the front rank must always be at least as wide as subsequent ranks, thus if there are 3 TG left he can still sit behind them, once there is 1 left though he must move forward.
id just like to know why your slann was charged by stegadons. was it like a lizardmen civil war? a revolution?