She is a very beautiful chicken and i hope she gets better....
the one thing i haven't seen suggested as to her problem is " blow out"
was she laying eggs at the time of this injury?
how old is she?
i had a Silkie hen "Scotty" she was about 3 years old and she had an injury similar to what yours does.
at first i thought she mite have jumped on something and punctured herself ( there were actually maggots in the wound)
so i brought her in and cleaned her up, applied antibioitics and she seemed to be healing great.. then a few days later it happened again...
only worse with MORE maggots..... i learned from a very knowledgable chicken lady what was happeing...
as chickens get older their inside lining can weaken and eggs can pop out of places where they are not supposed to.
the humane thing to do was to end her life as even though she seemed to not be in pain.... her suffering was not going to end and with each egg she passed ...
i hope this is not what is wrong with your hen