Hmmm...any signs of a respiratory infection because there is a mycoplasma infection that can cause joint swelling and inflammation.
I'm being tested four gout. If that little hen has gout she is experiencing a world of hurt!
I would suspect mycoplasma synovitis. How do the hock joints look? I have not seen articular gout, but in pictures, the whole foot and toes appear lumpy. If you do a necropsy there will be white urates deposited on the joints and on organs, which is a result of kidney disease.
MS may be treated with Tylan, tetracycline drugs, and others. I would recommend a vet.
MS can be diagnosed with a PCR test that may be done by a vet or poultry lab. Here is a lab I saw online:
Here is a good article on MS in poultry:
In this link there is a good picture of articular gout: