My five year old hen is behaving weird and don't want to eat

[Eggcessive]

I wish I could help more. I had a chicken die last year of a gizzard impaction, but I didn't know what was wrong until I opened her up after she died. I hope she recovers, Here are some articles to read about egg yolk peritonitis and internal laying:
http://www.chickenvet.co.uk/health-and-common-diseases/egg-laying-issues/index.aspx
http://scoopfromthecoop.nutrenaworld.com/tag/laying-issues/