One of my BA hens Petunia, has been acting lethargic for a couple days. Her poop is thick and yellowish . She is eating and drinking but not running around with the flock who free range during the day, just resting in the sun and keeping to herself a bit. She is about 1yr 3 mos old. I just started with chickens last year so haven't had much experience with illnesses as yet. Any advice from you more experienced folks would be appreciated.