I have a hen that her back under side has became large. To the point she really has to waddle to walk and even falls over at times. I have felt her back underbelly, it is very firm. She looks like at times she is trying to do away with waste, but she hurts. She had a lot of matter on her back side, I was able to get it all off. What could have caused them problem? I don't have money for a vet bill right now, or I would take her.