I have a chicken going through all of this now. The first thing I noticed was her slowing down and her eyes not looking at as bright or wide open. She just looked tired! I missed the first stage you mentioned. Then she went through the 2nd stage you talked about. Last night, she looked hunched over as she sat alone in the sunshine. Walking appears to be difficult for her now. This last winter has been hard on her, especially from the snow everywhere forcing confinement she isn’t used to. For a timeframe, I noticed the first signs about 3 weeks ago. I’m Guessing she will be gone this morning. I do feel like this has been a very natural and peaceful process for her.