Baby chick keeps falling over

[Wyorp Rock]

I have a 5-day-old baby chicken that was hatched naturally by Mama outside. She's a barnyard mix. She had a normal incubation length and an uneventful incubation.
She was found wet and cold out from under Mama shortly after hatch. Brought her inside and dried her off and left her up with a hair dryer on low speed low heat. And then returned her to Mama where she was accepted and stayed for the last few days. Noted baby has a hard time with balance. She'll stand but then fall over to one side.
She is acting normal, eating and drinking. She is not being picked on by her siblings. I find her most frequently under Mama instead of exploring the environment like the other baby chicks. Wondering if this looks like slay leg or if this looks like some kind of neurocognitive disorder.

I'm hopeful for any thoughts and recommendations.

I'd try giving vitamin therapy to see if she improves. I agree, it looks more neurological, she's also shivering a bit, hard to tell if that's a symptom or just a bit scared.

Give 400IU Vitamin E and 1/4 tablet B-Complex daily. A bit of egg with help with the uptake E. E is for neurological, the B-Complex has B1 and B2 which support E and leg health, the other B vitamins in the complex are essential as well, any excess is excreted in the urine.

As long as Mom is giving her warmth and tolerating the clingyness, I'd be inclined to leave her with Mom. She will fare better with siblings and integration with the flock if she's able to get to food/water o.k.

This sounds like Merck's disease. Our Bielefelder chick started doing this at 1 week old, and also fluttering it's eyes. The exotic vet told me it was probably Merck's disease.

Chick is 5 days old. Typically, symptoms of Marek's disease are not seen until around 8+ weeks old.