Chicken walks drunken like, HELP!

[Leanrz]

Hello-
I need some advice on what to do. About 2 weeks ago my 5 month old black sex link chick was sleeping in eggbox which is unusual. She easily let me pick her up which is also strange. I attempt to place her on roost but she fell off 3 times immediately after I let go. I quarantined her to my shed. I gave her apple cider vinegar to start with. For the last 5 days she has been on Bird Sulfa ( sulfamethoxazole Trimethoprim). I have tried giving plain yogurt a few times. Her appetite seems perfectly fine. She continues to walk like she is drunk tho using her wings to attempt to balance herself. Her R foot curls when not in use but flattens when she puts weight on it. I do not see or feel any injuries. She was acting fine earlier in the day. HELP!?! WHAT can this be, do I throw in the towel and put her out of her misery or wait it out longer.

 

[Eggcessive]

She could be showing signs of dehydration, a vitamin deficiency (riboflavin or B2,) or she could possibly be showing neurological symptoms of Mareks disease. First put her on chick vitamins that contain riboflavin on label or crush 1/2 vitamin B complex tablet into a small amount of food such as eggs. The earlier riboflavin deficiency is treated, the better the chances of recovery. Make sure that she can get to food and water. Here is a link to read about riboflavin deficiency:
http://www.thepoultrysite.com/publications/6/diseases-of-poultry/217/vitamin-b2-deficiency/

Here is some reading about Mareks disease that points out lookalike diseases, but I hope that is not it:
https://www.backyardchickens.com/articles/the-great-big-giant-mareks-disease-faq.66077/