I was reading through some of my old poultry magazines and came across a person with a similar problem, a polish with swollen feet so I will pass on the answer that was given.
The person said that it appeared to be inflammation caused by a secondary infection. This is usually a reaction that occurs after a respiratory or similar problem, but which can develop into a bacterial infection, causing swelling, providing the bird is mobile and doesn't appear to be in any discomfort it should be treated with Terramycin, a broad spectrum antibiotic, it is hard to cure completely. Claims it's very common. The magazine is based out of England, so just passing that on.
The person said that it appeared to be inflammation caused by a secondary infection. This is usually a reaction that occurs after a respiratory or similar problem, but which can develop into a bacterial infection, causing swelling, providing the bird is mobile and doesn't appear to be in any discomfort it should be treated with Terramycin, a broad spectrum antibiotic, it is hard to cure completely. Claims it's very common. The magazine is based out of England, so just passing that on.