I am new to this I have had chickens in the past and am starting over in new place I usually get rescue hens and build coops from different things, Lately I am re-fitting a cat cage for a small coop. They already like it and it is not finished. Also 40 years as a vet tech.
You have to be very careful if you are flushing a wound that is entering the abdominal cavity that can set up peritonitis. The edges of the 1st pics look almost healed, how many days ago do you think the incident happened?
When did the bad smell begin? If it is a ruptured abcess that would...