One of our hens, a year old Australorp, just today had had goopy yellow poop stuck to her bottom. I wiped her off this afternoon. She was very easy to catch, not normal. We came home tonight she was under the coop, laying on the ground. Again she was easy to catch and we put her in the coop. She is usually very mobile and active. As second in command in our flock of four, she is unusually quiet. We are worried. Also, can this spread to our other chickens or to us?