Chick with shakes/tremors, poor balance

[jconst]

In short:
Our 5+ week old chick is shaking and stumbling - pictures and videos linked. What might be wrong with her? Has anyone seen anything like this?

Here are the videos (in particular, any the June 3 videos are good for showing her current state. The dark brown one is the chick in question):
https://drive.google.com/drive/folders/1HgZDr3IgzdP4GOjHUZcGpYJ35s7TejBx

Details:

• Our chick, Speedboat, is a sexed Buckeye pullet from Tractor supply we bought about 5 weeks ago. We’re not sure if she received any vaccinations.
• Speedboat is 5+ weeks old right now. She has spent most of her life in a brooder with several other chicks, who have not shown any of the symptoms she has.
• A week ago we noticed she had some leg shaking/tremors and balance problems, but they were relatively mild until about 3 days ago.
• Now, whenever she stands or walks, her legs shake a lot, and she has awful balance. When she’s startled or excited, she stumbles across the brooder, and she often slams into the walls as a result. However, when she relaxes and sits down, the shaking is barely present.
• Also, in the videos and the attached photo, you can see that she generally doesn't stand on just her feet, but with her lower legs sort of bent down. I assume she does this to help her stay steady.
• She has a lot of energy, she eats and drinks normally, and she scratches at bedding with her beak to find bits of food. Her head and neck seem ok, and her eyes look ok. But when she’s up and about, she is constantly stumbling around and shaking.
• Her peeping sounds are quiet and hoarse.
• All 3 chicks have been sneezing a bit recently, and we hope it’s because of the paper bedding we used for a week or two, which we have recently replaced with cedar.
• We’ve been feeding her Prince Starter Feed, but for about a week or two we didn’t have access to chick starter, so we fed her Prince Layer Feed. We have since switched back to chick starter, and starting today, on a recommendation, we’re adding “Rooster Booster” vitamin and electrolyte supplement (see our pictures of the label) to the chicks’ shared water. We also offer them clover and kale from our yard.
• We don’t want to feed the healthy-looking chicks unnecessary extra vitamins, but we’re hesitant to separate the chicks at this point, for fear of making Speedboat stressed and lonely. We also want to give the chicks a bigger space to play and forage, but we’re playing it safe until we can determine whether they have something that can be spread to our established flock.
• Another Buckeye from the same group passed away at about a week old, but was actually kept separately from Speedboat after being purchased. The other two chicks (Ameraucanas) have both been fine. At a young age, Speedboat had a clogged vent, which we cleaned, and it has seemed normal since then.
• We haven't noticed anything strange with her eyes, which we have photos of in the Google Drive link. (We read that the eyes sometimes show symptoms of Marek's disease.)

Thank you all so much in advance for any advice! We are very worried about her and about the rest of our chickens if this is contagious.

 

[harice4806]

You said you're using cedar get rid of it ASAP. The cedar oil is deadly to chickens. Start there and see what happens.

 

[jconst]

You said you're using cedar get rid of it ASAP. The cedar oil is deadly to chickens. Start there and see what happens.

Thanks, will do. We just put the cedar bedding in today, though, so that wouldn't be the cause of the problem.

 

[jconst]

I replaced the bedding with pine yesterday, unfortunately no difference in the chick's behavior today