Black cochin hen walking on hocks. Advise?

[Jnokomis]

I have a beautiful black cochin that back in late August/Early September began limping on right foot. I caught her and checked her foot and leg as best I could finding no sign of injury. She would drag it a little if chased (like when I tried to catch her) otherwise limped. After a month she seemed to give up on limping around and now walks on her hocks. She eats well, drinks well, poops well and she goes out foraging with her flock. She can be feisty at times and will bite at me when I try to pick her up though some times she seems to want to be spoiled and will wait for me to pick her up and carry her to the coop. I see no other signs of injury or illness, and she never balled her foot up. I have 14 hens total plus 5 muscovy. No one is showing any illness or signs of being lame, she is the only one who is not walking right. They live in a shed I converted to a coop. I have made a roost from precut stair raisers and 2x4 that is 5 steps high. The bedding is pine chips. I'm not sure what else to add. Any advice?

 

[Eggcessive]

Have you tried treating her with poultry vitamins including riboflavin, in case she has a deficiency? That is what I would do—either give a poultry vitamin, or give 1/2 human vitamin B complex tablet crushed into some food daily, such as a little egg, yogurt, or tuna. Beef liver would also be a good source.

The lingering thing in my mind is that she could possibly have Mareks disease, which can cause walking on hocks or paralysis of one or both legs or wings. Injury might also be the problem.