Photos are always welcome.
It's still unclear whether there's a mite infestation on the bird(s) and in the coop or not.
Hard to know what's happening, it may be time you send a body to your state lab for necropsy/diagnostics, if you lose another. This will give the most information so you...
You can use the Permethrin in 5-7 day intervals to treat the mites. They can be extremely hard to get rid of.
I'd re-check the birds to make sure that they have no mites on them, mites will suck the life out of them, make them sick or can sometimes kill a bird.
Ivermectin Pour On can be...
Photos? Please? Can you please post Clear Well-Lit photos of the Silkies, their eyes, feet, poop and of them?
Thank You!
Mites. How have you treated the mites? I'd re-check for mites.
Earlier this year, looks like you had Canker in your flock. Did you get rid of that? Have you checked to...