On of my bantam hens has been acting very lethargic for the past few days. She stays hunched over and seems to have a swelling on the left side of her neck just below her head. Her eyes look hazy and I don't think she is eating well. Just this morning, I noticed my rooster Pretty Boy is now not crowing and is keeping his wings close to the ground. I am worried. I only have one other hen in the pen with them (they are in by breeding pen.) I want these chickens to be okay but most importantly I want to prevent what ever this is from spreading. They are on a healthy diet appropriate for laying bantams and their pen is clean and neat. They have clean/dry housing and plenty of roosting and nesting space. My husband said that he noticed some green droppings in there this morning. I have isolated the hen that is still looking/acting normal. Please help!!! Here they are about a month ago looking healthy!