I need some help finding out what is wrong with one of our hens. About a few months back I found a snake in the pen, and tried to kill it but to no avail. I didn't see it for a while, and then one day I saw it again. Yet again, I couldn't kill it. The next day, I went outside to feed and check for eggs when I noticed a hen who was lethargic. It was sitting in front of the door and didn't want to move. Eventually it moved slowly, and hobbled off, and kinda leaned on its wing. I told my Dad and he said that it had been like this for a week (how he would know is beyond me, he rarely ever checks on them, he leaves it to me) and that it was our rooster that did it. I checked it for marks and wounds but found nothing. We separated her, and it's been at least a month since then and she's made little to no progress. She sits in the exact same spot all day and night, near food and water. She seems in pain, and I hate to see her suffering. I think it's about time to put her out of her misery, but I don't want to. Is there anything I can do? Is any more information on the chicken needed?