Gretel my oldest chook has suddenly gone downhill. She seems to be limping and very unbalanced - drunk even, keeps sitting down on her bum and falling over. I think she is 4 years old.. but possibly nearly five. She has always been a very entertaining and friendly little buff and I love to watch her skipping around the yard, but she has lost all the spring in her step over the last day or two. I picked her up and could not see any evidence of injury anywhere on her, and all the others in the flock are fine. I have read about mareks but all the info seems to infer that only young poultry get it. I don't want to have to dispatch her off to meet her maker but will if I have to, she is a bit miserable. Please any advice would be appreciated. We are in New Zealand, currently experiencing hot weather and drought.