My 2 yr old EE hen has a messy rear end. Lots of feces stuck to the feathers. She seems in good health otherwise, eating and drinking, not thin, and no sign of mites. I have separated her from the others and plan to deworm them all tomorrow. Two questions: what is the correct/best dewormer to use? There are a lot of threads on here about that, but I can't figure out a specific brand/product. Second question: do I need to keep her apart or is that unnecessary? Thanks in advance!