Johnny, this is better asked on the general section,
Egg is the mother of stains to remove, I had one a few years back, and nothing at the time would touch it ( any very little knowledge of chems then ) after 3 hours I told them to repaint the side of the house - yellow render
I would have a crack ( pardon the pun ) if you can reach with a hypo mix - but this depends on if your roughcast is painted or not.
HTH
Darran