We have a 6-month old black australorp who began acting very lethargic with no desire to eat or drink today. She regularly released bright yellow and white diarrhea looking droppings - most were very runny, with the exception of one that was paired with a slightly more standard dropping. Her tail is dropped and she had almost no desire to forage with the rest of the flock today - she just stood in the same place with her feathers puffed out. We have since brought her inside and have her quarantined in the basement with a heat lamp (it's below freezing tonight). She does have a couple of black dots on top of her comb that I assumed was mild frostbite, but now I'm concerned that she may have blackhead disease. Based on the droppings photo and description, does anyone have any ideas about what may be wrong? They were on medicated feed up until a week ago, so I haven't done any deworming yet - we are new to all of this so weren't sure when you needed to begin that process. Thank you so much in advance for any help you may be able to offer!!