I got my chicks yesterday, all seem to be doing great. I was holding them and giving them a look over when I noticed one had poop? on it's bottom. Thinking it may be "crusty bum" I wet the area with a warm paper towel to see if I could get it off. It didn't want to come off. While doing this, the chick pooped. This crusty area is not on the bum. What is it? Should I leave it to come off on its own or continue to moisten it? The chick doesn't seem bothered. Thanks