Just wanted to give an update. The thyme tincture alone cleared up all the plaque after 10 days.
She began eating and I went back and forth about returning her to the flock or culling still. I decided that since I’m now aware of the copper sulphate as preventative, they will be fine. I’m so grateful for that information. I free range them and watched how they daily drank from any tiny pool of water around the property. It’s inevitable that they’re exposed to canker this way from other birds.
So based on that reality, I decided to let her be free, she appeared to have enough strength to withstand a roo. Within a day she had cleaned herself up and was integrating as normal, eating, drinking and all!
All is well here, although now I’m watching one Roo grabbing my girls fiercely by the combs and that caused a scare with the several having black scabs, it’s always something isn’t it!!!???!!
Thanks for all your responses and help!