When the moathouse was taken, part of the
drawbridge was battered through, and men
crossed on planks to gain access to the inner
gates. The chains of the drawbridge were broken,
and it fell; it has remained thus since. It is
strong enough to bear a man, but any mount
crossing over may break through and injure a
leg. The chance is 50% for a horse, 30% for a
mule, and 20% for a pony. The injury reduces
the mount to 2/3 of full hit points (rounded up,
permanent until magickally cured), and reduces
movement rate and encumbrance figures to
1/2 normal.

>> 3.