May I jump in here and ask a question?
A couple years ago I had a hen who got a sore on her bottom (under and to the side of her vent). It appeared to get infected. I gave her antibiotics. The outside healed, but the area became a bit swollen and hard. I was thinking it was just fibrous tissue from the previous infection. She never really recovered from it. She improved somewhat, but was never totally healthy again, and died when I tried to reintroduce her to the flock. They attacked her and I immediately took her away from them, but she died shortly afterwards. I didn't realize how compromised she really was.
Anyhow........after reading several posts about how abscesses get hard, it makes me think that this hen had an abscess and I didn't realize it. Is it possible that it festered for weeks, and even though she appeared to be recuperating, it just eventually overwhelmed her?
Do they ever wall themselves off and keep the chicken from getting sick systemically?
I'm really glad I learned how their abscesses behave. I might have been able to save her, had I known this then.
Thanks for enlightening me!