Did the swelling increase by now?
If so and on both feet it might even stem from some kind of organ failure.
If it is just on one foot it might be caused by a tumor impeding proper blood and lymph flow.
Slow growing tumors might start to restrict blood supply and/ or pressure on nerves and intestines which will make her feel increasingly uncomfortable and weak.
When I noticed one of my oldest hens starting to limp and resting more while the others went about their day, I dewormed her...
In your first picture her crop looks distended and quite low. Check her for crop impaction. Did you check if it empties properly over night?
Highstepping with the right leg can sometimes mean that the bird is trying to adjust or push an extended crop.
A partial crop impaction could also lead...