Any unit taking 25% or more casualties of its current strength from shooting during a single shooting phase must check against its Leadership not to fall back.
-1 If the unit is below 50% starting strength.
EXAMPLE: A unit of five troops suffers two casualties (reducing it to 60% of its starting strength) so it takes a Morale check. Next turn the unit, now three strong, suffers another casualty (reducing it to 40% of starting strength) so it takes another Morale check, this time at -1 Leadership for being below 50% of starting strength.