I'm a little confused, because I thought pasty butt was more frequent when chicks were too warm. I've not had to deal with it, so I have no direct experience.
Same here, not sure what causes it, just thankful I don't see much of it. My new chicks are on regular dry chick starter, older chicks on fermented chick starter. Does the fermented feed help? I think so. Pasty poots are pretty rare in my flock (knock on wood!)