If you should have any reoccurance of pasty butt try putting a little raw apple cider vinegar in their water. Bragg's is a common brand. A teaspoon per quart of water, it works really well to put a stop to pasty butts.
I feel like such a monster, I just had to get the pastyness off of all but one of my chicks, and they complained so loudly A little bit of down came off of each one, they will be ok right? It's not going to hurt them a lot?