If this long response suprises you just remember; Crud is my middle name.
Anyway:
They were called Garderobes and were:
"found in different locations and usually projected over a blind wall, like a window box. The garderobe was outfitted with a small bench with a round opening on the seat, which, more often than not, opened directly over the moat[if the castle had a moat]. Wherever a primitive sewage system had been installed, the waste was born down to the lowest level of the tower, which acted as a large cesspool and obviously could not be used as the dungeons of 19th century romance[the writer seemed upset with the idea of prison dungeons below castles and he put the idea down in several places throught his book
]. About twice a year the peasants would have to clean out the cesspool." quoted from The Medieval Fortress by J.E. Kaufmann & H.W. Kaufmann with illustrations by Robert M. Jurga
There is also a depiction of a garderobe that is a tower-like structure which is seperate from the keep/castle and is accessable only by a longish bridge structure that goes to the top of that wonderful place.
The peasants sure had it rough. Add that on to cleaning stalls... ugh. Hmmm... more motivation for TLC to recreate the pitchfork?
From wlister:
proper names for the collection and removal of waste
HA! Let's not mention those here!(just kidding dude)
I didn't know they had a name. What could it be? I think it would be best if I didn't guess.
(Actualy Crud isn't my middle name. Just so you all know. No I'm serious! Aww come on, guys, ya gotta believe me! *sigh* Never mind)
C
who could forget this one? 
dang...I gotta lie low here...
