Very sick older hen - advice?

[sjmjrgkmg]

Hi all,
One of our "elderly" hens - about 6 y.o. - has been doing poorly lately, but went downhill very quickly. I found her on the coop floor, unable to stand. She seems to have paralysis of legs, very messy diarrhea (brown - profuse) and is not eating. If I prop her she'll stay in that position, but her feet are curled up to the side. Her comb/wattles color isn't good and she just seems like she's failing rapidly. It's really cold here, so I have her inside for the warmth. Will only drink if I squirt it into her mouth with an eyedropper. Yesterday she gobbled down some kefir with ground cereal grains in it, but won't look at it today.
I live in an urban area, so few vets treat poultry. I tried some epsom salts solution (couldn't get much into her - how do you get a chicken to open its beak, anyway?). The nearest store with poultry antibiotics is a few towns away, and we have a snowstorm brewing. Any advice gratefully received!

 

[enola]

Have you checked her for lice? Wormed her? Is she thin?

 

[sjmjrgkmg]

It's hard to tell if she's thin - she's a very large, fluffy breed. She hasn't eaten much in a few days, so she's light. I didn't see worms, nor lice - wouldn't all of my flock have them if she did? Everyone else seems fine.