Hen won't use leg

[KaOsFarm]

I was unexpectedly gifted a hen who seems to not be able to put weight on her left leg. She is thrifty and eats well. She won't roost and only lays down. I didn't realize it was a leg issue until today when she very visibly refuses to bear weight on it at all anymore. I am new to chickens so I don't know how to treat her or figure out what exactly is wrong with her besides the fact that it is her leg. I did notice that it was significantly warmer than her other leg but I can not find any injuries on her foot or leg. We are in the middle of a blizzard so the vet is not an option at this point. Nothing appears swollen. I have her in my house at the moment.
How do I asses it? Can I brace it?

 

[chickencheeper]

Check her feet(the bottom) and take a pic so we can see what it may be

 

[Chelseyb123]

Definitely take a picture of itm but is there any signs of bumble foot?

 

[Eggcessive]

I would keep her in a basket or dog crate with food and water near to her, just to force her to rest it. Every day, take her out, and see how she is doing. It could be an injury, a vitamin deficiency, or possible Mareks, but I would look at the first 2 possibilities first. Look at the bottom footpad for a scab, and look at the joints for swelling, redness, or for any bruising. Compare the size of both legs. Get some poultry vitamins containing riboflavin, or use vitamin B complex, or some beef liver.