Need help! We have a chicken that is struggling to walk and staggering backwards.

[AngelinaThePekin8]

It is just under ten weeks old, none of them are laying eggs yet and I'm guessing it is a rooster anyway, it seems to be eating and drinking fine, I mixed up some electrolytes, vitamins, b complex and probiotics in water for it after we noticed the issue, I felt around on it legs and feet and didn't find anything. We feed them chicken feed and fresh vegetables out of the garden. I haven't inspected its vent yet. I am at work right now but I will inspect it's vent and droppings when I'm able. I have it seperated right now so the other chickens don't try to pick on it, except for a hen I put in with it so it doesn't have to be alone. Also, does everyone see the video link now?

I was able to watch the video don't know about everyone else

 

[Ladyaspen]

Here is the video link.

I have a sexlink hen just started doing this yesterday. Still eating drinking and pooping. No visible injuries. Examined her. No lice Mites. Worms. Gave her ivermectin and vitamins in water just in case. No improvement today. Did you discover what is wrong?