I had a chicken that did that a year or so ago. I posted the problem on this board, and one person (I wish I could remember who it was!) said to try Vitamin B Complex. I went to the store and bought capsules (for humans). Being capsules, I could pull them apart and pour out the powder. I poured it on all the chicken,s food and in all the water (chicken was in a cage so had exclusive access to some food and water). I didn't pay any attention to how much I was using...I just continued to put the powder in all the food and all the water, because I doubted an overdose was even an issue at this point. Much to my surprise, she started walking in about 2 weeks. Not well at first, but each day was an improvement. I finally put her out with the others. Of course she had to defend her place in the pecking order, but she was OK. It wasn't long before she was walking normally, and I was very shocked. It was funny that she suddenly started to crow! I had thought for sure he was a hen....but turned out to be probably the biggest rooster I have, with huge strong legs.
Your chicken may have Mareks disease...I understand that can cause them to become lame. But trying the vitamin won't hurt, and hopefully you will be as lucky as I was.
