4 year old Australorp hen wouldn't get off the roost today (empty crop), no interest in scratch, ruffled up, so I brought her inside to observe. She's finishing her molt but not laying yet. We free range all year, layer feed available in the hen house. Very little appetite, tiny voice, pale comb & wattles (molting). I coaxed her to nibble at the oatmeal & yogurt, a couple seeds, a couple baby spinach leaves (very little eating). Pasty vent. Watery, mucousy dropping with occasional blood tinge. Sometimes her urates are creamy & light yellow. No sneezing or facial discharge/swelling. No visible swellings on legs/feet. My first thought was blackhead, but I understand this is rare and doesn't usually effect chickens. Cocci? E. Coli? I'm starting her on tetracycline. Unfortunately, none of the vets around here know birds. I use DE for worms, but haven't added it to the feed since August. Any thoughts?