One of my black sex links had been acting strange the past few days, not coming out to free-range with the flock and sitting alone in a corner of the coop all huddled up. She has diarrhea (some stuck to her bum and I've seen her be ill) and I've found traces of mucous and blood in her discharge. She seems very very quiet. My contractor is working on the coop and said that one of our silkie roos wouldn't leave her alone this morning, he was mounting her incessantly and pulling her head feathers and all. Eyes are clear, feathers shiny, she doesn't feel thin, vent is clean and looks normal. But she's not acting normal. Is she ill? How can I clear up her diarrhea? The rest of the flock is normal - please help!