My girls had a respiratory illness spread through the coop. Patient 0, Melba, was starting to do get over the cough and sniffles when I put the whole flock on Tylosin. She completely lost the cough and rales but the morning of day 3 of antibiotics she became lethargic, hunched up, drinking but not eating, not really pooping. Today is day 2 of the same. I’ve attached pics to help illustrate. Any thoughts as to what it could be? I gave them all yogurt the evening of day 2 when she was perfectly fine and energetic, and then she was yucky the next day. She is extremely skittish and she won’t let me touch her so I can’t feel crop, though it looked flat, and can’t check her vent closely, but did look like there a bit discharge. Please, any advice is appreciated!!!!