3 year old hen is not moving

Hi everyone, this is my first post, but this site and its members have been instrumental to my family's backyard chickening...

I have 4 hens, 3 are 3 years old and the other is 2... The dominant hen has taken ill about two days ago. It was practically overnight. She was fine one day and now is just laying down and won't move for anything. She isn't paralyzed as she will rock to one side occasionally. I moved her to a large kennel with plenty of straw and pine shavings to isolate her from the others. I have read a lot about marek's, cocci and worms and have not seen any signs of those. Her eyes are fine, no swelling in legs or body, but I haven't noticed a stool in a day. I have been feeding her scrambled eggs, yogurt, a single tums (for calcium), water and organic apple cider vinegar... The only symptom, besides a little weight loss and being tired, is a dark red comb and wattle (almost like red wine) and her chest is a little bare. Her crop is fine, i have checked for ticks and lice without a trace... She doesn't chow down on food, but i think she has wasted in the day it took me to figure out there was a problem... So I don't expect her to have an appetite just yet. She has been my most productive hen and stopped laying about 4 to 5 weeks ago, when she went broody for a week or two (also when she plucked some of her chest feathers, which appear to have not yet grown back).

Please help. She is my Gigi and a beautiful black Australorp...

same here sorta, i walk out and usually everyone walks to me... NOT TODAY.... they were so hot they just sat there and i got my first egg today.

No it hasn't been very hot, but we have had a lot of rain over the last two weeks and the ground is saturated, even under their covered run. We are in Colorado and it is typically dry, but we have been having more rain than the last several years... I wonder if that has stirred anything up?

Here's my girl... She will eat and drink and shake out her neck...

Check and see if she has an egg stuck in her "egg hole" Thats what happends sometimes. Good luck

I would wonder if she has egg yolk peritonitis or internal laying with the weight loss, not wanting to walk around, and not laying. You also don't need to see worms for them to cause a problem. Look her over for lice and mites too. I would take a rubber glove, and feel inside her vent 1-2 inches just to see if you feel a stuck egg or anything unusual. Watch her poops for any abnormal looking ones. Here is some reading:
http://www.chickenvet.co.uk/health-and-common-diseases/egg-laying-issues/index.aspx
https://www.backyardchickens.com/t/526089/egg-yolk-peritonitis

Thank you eggcessive.

You're welcome, I hope you find out what the problem is.

How is she?