Lifting leg high when walking?

[Chickentender7]

I just noticed my 3 month old hen has started high-steping/limping but I looked back at our coop camera and it seems she's been doing it since wednesday-ish so 4-5 days. It won't let me attatch a video so here's a couple pictures. The first photo is showing her mid-step.
She holds her left foot up close to her body and tries to hop around on her right foot. When she lays down, she curls her left toes up.
I've inspected her leg and foot, I dont see any visible injury or bumblefoot. She is eating/drinking/pooping normally, she's just really struggling to get around so I bring food and water to her. She stayed in the coop this morning until went and physically took her out. She's not socializing as normal, just keeping to herself.
What could be going on? I was thinking maybe a sprain?

 

[Eggcessive]

Hopefully, it is a sprain or injury to the sciatic nerve in her leg. But Mareks disease can sometimes cause numbness and curled under toes in one leg. I would probably place her in a dog crate with bedding, food and water near the other birds. That will force her to rest the leg and may protect her if they should start to pick on her, as chickens may do when one is stumbling. I have seen high stepping of both legs in an arthritic older rooster before. I would get some inexpensive super B complex vitamin tablets, and crush1/2 tablet daily in some soft food or egg. A chicken sling might be helpful if she stops walking. Let us know how she gets along. Here is a good buy on B complex:
https://www.walmart.com/ip/Spring-V...MIrqzut7j0jQMVf1tHAR1pvwhSEAQYBCABEgLis_D_BwE

Here are some good examples of chicken slings and chairs in posts 5, 11-14, and 31:
https://www.backyardchickens.com/threads/versions-of-chick-chairs-please.1166308/