I am guessing that by crystal you mean the spawner its self, each of those spawners probably spawn other creatures than just sheep. It is likely you will have to go to each of them and remove sheep from the list of things that they spawn.
Posted By paradyme - XML Commands .xmlhome returns the coordinates of the spawner for the targeted object. Also takes arguments: •go that teleports you to its spawner, •gump that opens its spawner gump, •send that sends the object back to the spawner location Example: .xmlhome gump .xmlshow...
And this is the question "Cu Sidhe" has a rare color system implemented here? You do not need to configure anything, just when it appears, there is a chance that Cu Sidhe will appear with a rare color?
There may be an easier way, but I have an idea that should work. Use the xml find to get all the sheep spawners. Then open each spawner and remove the sheep from the list. Sounds tedious but effective.