I have heard of pasty butt and all of the pictures I have seen are no where near as much as this. Can anyone tell me if this is pasty butt, how to treat it and if it isn't pasty butt what is it?
Looks like pasted bottom to me. My goodness, is your chick not completely freaked out by you holding it like that?
You have to wash it off, gently. A cotton ball soaked in lukewarm water is good and lots of patience. It will take a while to soften the poo enough so you can wipe the poor chick clean.
For us, adding a bit of oatmeal to yoghurt as a treat did the trick. I only had to clean up two chicks one time.