Yes, organ reeds break.  They do not fatigue, but brass is an alloy
of zinc and copper.  As you have seen in a zinc organ pipe, after
some years the solid gray color of the zinc turns into a multifaceted
crystallized look found on pipes older than a few decades, and if you
crease the zinc it will break.

With age, brass develops the same crystallized molecular structure and
becomes brittle.  With enough use, every 100-year-old reed will break.

Just like piano rolls on acid paper, all brass has a limited life.
This is why every reed organ I restore I do what the old guys told me
will de-crystalize the brass and give it a longer life.  It first
started with brass rails in piano actions.  I now use it on organ reeds
as well.

Scoff if you will, but I believe that if I do what the old guys said to
do, my brass reeds and rails will not break in the near future.  I can
say that in the last twenty years of doing this I have never had a
brass rail or reed break after treatment.

Put the brass in the kitchen oven and heat it to 200 degrees F.  This
is a low heat used mainly for warming food, so we are not talking about
really hot here.  Leave it in the oven for one hour and turn the oven
off.  Leave it to cool in the oven overnight.

'De-stress' and 'de-crystallize' are words used for this process.  It is
not annealing or tempering, as those refer to high heat which would
damage the item.

D.L. Bullock    St. Louis
http://www.pianoworld.us/