An easy way to clear up pasty butt fast is to just put about a teaspoon of raw apple cider vinegar in the waterer. A common brand is Bragg's. (1 teaspoon per quart) Once you get the chick butt cleaned off apply a little olive oil around the area to help prevent further buildup.Yes, it seems everytime I get new chicks at least 1 gets poopie or crustie butt. One I have now anus looks swollen too. I am doing the yogurt plain and warm water compresses. Often the one in distress churps continuously also. Belly ache. I was told that in the wild they eat some of mommy's poop and this clears it up. For the probiotics. I read something about olive oil once? Don't remember which end it was for though. Hope all chickies are ok. They have to poop or they get very churpie.