my hen is 4 years old and I found her at the edge of the coop door. She can't walk or stand up, so she just huddles down where ever she manages to flop to. This happen once before over last summer and she wasn't better for about two weeks. I know she isn't egg bound, I've already checked. And last time this happened her droppings were greenish yellow. She will cluck, but unlike usual, she won't struggle when I pick her up. It gets down to the low 20 degrees at night, but she's under a heat lamp now. Does any one know what's happening, because she barely lived last time, and after the first time, she became unable to eat treats, or fly and jump.