My chicken about a week ago got sour crop and seemed to get better but turned for the worst. She has always been a bigger chicken but has lost severe weight and has lost her appetite. She has runny greenish yellow diarrhea and stands like a penguin. she is very weak and constantly closes her eyes. I checked to see if she was egg bound but that doesn't seem to be the case. she also shakes slightly. please help I'm out of options and after I lost my beloved pet duck to a dog my pet chicken Kentucky has became my friend and now i'm afraid to lose her too. she is also little over than four years old.
I'm sorry to hear about your hen

If you have photos of her poop and of her you would like to share, that would be good.
Do you know when she last laid an egg?
When you checked to see if she was egg bound, did you notice if she had any swelling/bloat or feeling of fluid in the abdomen (below the vent, between the legs)?
You mention that she had sour crop - is her crop empty in the mornings before she eat/drinks?
Getting a fecal float to check for worms is always a good idea. With the symptoms you describe, standing like a penguin with weight loss and lethargy, I would suspect that she has a reproductive/internal laying disorder like Egg Yolk Peritonitis, Ascites, cancer, tumors or Salpingitis.
You can try soaking her in a warm epsom salts bath to see if that will soothe her. See that she is drinking well, then offer food. Re-Check the crop for several mornings in a row to make sure it's emptying properly.
http://www.scoopfromthecoop.com/laying-issues-internal-layers-and-peritonitis/