Those little critters can give a wallop.
A hematoma is simply a scab that forms from coagulated blood under the skin. Sometimes it will become absorbed and othertimes it will not.
Roosers wander around in some icky substances so there is the possibility of an infection.
My ex-girlfriend's farm has a number of them strutting around waking everyone up, and in shooing them "there, but for the grace of god, go I."
Doctornee gave a good suggestion, but I would ask around some vets or someone else who owns a chicken farm.
Hi
Welcome to the MedHelp forum!
The knot could be a hematoma (localized collection of blood) or an abscess or even a ganglion due to injury to a tendon. A ligament or a tendon injury could also be causing pain. Since you are still having pain and a swelling, it would be good if you could consult an orthopedic specialist. Hope this helps. Take care!