Partly paralyzed / injured? chick

[Magnayen]

After tons of lurking I have finally decided to ask you for help, because I'm all out of ideas. I have a langshan chick at 8 weeks old that can barely walk. It's always putting the left leg ahead and pulling the right leg from behind to stumble forward. I noticed it ~2 weeks ago when I was in the coop and this chick wouldn't stop shaking, so I brought it inside. At first I thought it was just cold, but when it didn't get better the next day I suspected an injury or vitamin deficiency. I don't think it's marek's because of it's age, and the whole flock is regularly vaccinated for Newcaste disease. I now have it isolaed in the living room and I gave it a vit-b-complex tablet once a day, but nothing has changed since - for the better or worse. I just want to know if it's treatable or if I have to cull, or if there's even a way to know.

I thought some expert might have an idea what's going on with this chick based on how it walks:

Here's the ingredients of the tablets I tried (I gave 1 tablet a day, whole, directly into it's beak)

Any help is greatly appreciated.

Edit to add: It's eating (a lot) and drinking fine, poop looks normal.

 

[Eggcessive]

It is very hard to see what is going on because of the feathered legs. I would guess that there is a leg bone deformity that has worsened. Those include varus or valgus deformity in one or both legs, and rotated tibia. None of those can be treated. Does one or both legs seem bowed in or out? You would be in a better spot to see what is going on. Is the chick on a balanced chick grower feed? Injury could also cause a tendon issue. Here is some reading:
https://www.uoguelph.ca/ahl/lameness-disorders-poultry

https://www.thepoultrysite.com/articles/leg-health-in-large-broilers

 

[Magnayen]

It is very hard to see what is going on because of the feathered legs. I would guess that there is a leg bone deformity that has worsened. Those include varus or valgus deformity in one or both legs, and rotated tibia. None of those can be treated. Does one or both legs seem bowed in or out? You would be in a better spot to see what is going on. Is the chick on a balanced chick grower feed? Injury could also cause a tendon issue. Here is some reading:
https://www.uoguelph.ca/ahl/lameness-disorders-poultry

https://www.thepoultrysite.com/articles/leg-health-in-large-broilers

Thank you for your response and the links. I already checked the legs over and over, and I can see nothing wrong with the shanks, toes or joints. Nothing's bent or swollen, nor turned sideways, the leg bones are all straight and the joints behave normally when I manually move them. It just seems like it can't put weight on it's leg(s)? for whatever reason. Weakness? Pain? Something with the hips?

I have like 50 other chicks, all getting the same grower feed and all are fine except this little fella.

 

[Eggcessive]

I would get some human super vitamin B complex tablets and crush 1/4-1/2 tablet into food or a bit of water daily. Here is a good buy:
https://www.walmart.com/ip/Spring-V...MItOiByJ2yjQMVTEdHAR2DpCMjEAQYASABEgKGafD_BwE