One of my hens has had diarrhea for two days and now another has a dirty butt. The poop is semi formed at times, brown, but squirty and liquidy other times (sorry about the descriptions). I had given them some watermelon, but not tons. Other than that their diet has not changed. I've had chickens for ten years now and never had an issue so I don't know what to do. Do I go to TSC and buy some wormer? Put vinegar in their water? Give probiotics? All of the above?