Chicken seems dizzy, unsteady on her feet. Sits down alot.

[CatUT]

I have a Jersey Giant hen that looks fine but she seems unsteady on her feet and will only walk a few steps and then sits down like she's sitting on a nest. I've separated her from the flock. She seems to be eating and drinking OK. She's still laying eggs. She's about 4 years old and the other Jersey Giants that I got at the same time are fine as are all the other chickens in my flock. I've looked at her feet and I don't see anything different about her feet and the other birds. I'm at a loss as to what is wrong with her. Any help would be greatly appreciated.

 

[Wyorp Rock]

Is her crop empty in the morning?
Any bloat/swelling or fluid in the abdomen?

Check her over for lice/mites, no crusty or raised scales on the legs, no signs of bumblefoot/scabs or debris caked on the underside of her feet?

I would watch to make sure she's eating/drinking, if she's struggling to get to food/water, then helping her along with that would be good.