I have a 8-9 week old Polish the loses it's balance and can't seem to stand or walk for very long without falling over. I got him along with two other polish chicks and the others seem fine. He is eating and drinking and there are no signs of injury. He has been like this for almost a week where some days are better then others like yesterday he seemed to be getting better but today he is worse. I have been giving him vitamins for the past two days and making sure he has been getting plenty of water.
Your little cockerel looks like he could possibly have Mareks disease or some other neurological problem that is affecting his balance. Are one of his legs paralyzed? Do the toes on either foot curl at times or all of the time? Does he walk or sit on his hocks or elbows? Mareks disease has 4 different types, and the symptoms can vary with each chicken. It can cause eye problems, skin problems, internal tumors, or paralysis, but the same chicken may only show 1 or 2 of these. I certainly hope that it isn't Mareks, so I would look at poisoning or vitamin deficiency as possible causes. In the meantime, I would start some poultry vitamins in the chicken's water. There are some decent brands at feed stores and online. Avian Super Pack 1/4 tsp per 5 gallons of water is one found here: http://www.randallburkey.com/Avian-Super-Pack_ASP-4-oz/productinfo/26094/#.U-j1uPldVWN Here are some links on Mareks: http://extension.unh.edu/resources/files/Resource000791_Rep813.pdf http://partnersah.vet.cornell.edu/avian-atlas/search/disease/502 https://www.backyardchickens.com/a/the-great-big-giant-mareks-disease-faq
he may have tore a tendon also. but i would try to make a leg brace for him out of wire and see what happens if not you may have to put him down sorry.