Thank yall so much. And thank you Kathy.
I'm sorry but I should have been more clear in my first post. This is the first chicken I have had that GOT sick from unknown source. When I first got into chicken keeping, my over enthusiasm and inexperience caused me to twice purchase birds that were already sick. They then infected birds I already had. It was a nightmare. Eventually though, I isolated and culled enough to stop it. Everything was sanitized or destroyed with fire.
I've had really good thrive going on since then with my flock. I thought it was over
This particular bird this time was in the process of being integrated into my outdoor flock,(outside in daytime, back in indoor cage at nights) so I'm a bit worried