I have 6 cornish x. A couple of them have dirty butts. Not pasting up or anything, it looks like they have diarrhea. They are all acting fine, eating, drinking, walking around like normal. They are a week old, and there is a silkie, EE, and 2 leghorns in the brooder with them who are acting fine and clean. These are my first meaties and everyone talks about what gross lil monsters they are, so I'm not sure if they are sick or just lacking in the hygiene dept. They are on medicated feed, I put poly vi sol in their water every few days. I clean the brooder every couple of days, and put fresh shavings in a few times a day wherever I see dirty spots.