Chickens will single out and kick out birds that act off for the good of the flock, since Alma is a little gimpy , she's a target. The small area likely doesn't help, a coop like that is only big enough for 3 birds.
You can rehome the aggressive bird but another may take her place.
It's likely just a soft molt then winter break. Switch so a nicer feed if possible, not organic as they're typically not great. And reduce the scratch for longer lives.
This is an older thread, you're not likely to recieve an answer from the op. Ivermectin is not good for treating worms, not knowing what was wrong with your hen, there's mo telling if it helped or not.
I think they ( they sellers) can decide what percentage off the system offers, it's just a really pathetic offer. I was going to offer more but there's no option to counter, sadly.
"Seller has sent you an offer!"
*Was $17.00, now $16.85!*
Wow, man. Shut up and take my money! How can I resist such a lucrative and generous offer !
I'm gonna send him a counter offer for $16.50, for I am a wheeler and dealer./s
Are they also molting? Are you sure it's mites?
Have you cleaned out the coop completely, treated it and gotten all new bedding and litter?
I would recommend you stop the Diotomaeceous Earth, it's not effective for mites, causes skin dryness/feather breaking and it's like breathing asbestos...
They won't do any more protecting than say, a dog and not only can be a threat to children but to adults as well.
They aren't animals to be taken lightly .
I'll tag some people that can help you.
@KsKingBee
Coccidia are always present in all environments, all chickens exposed to the outdoors have them. It's when you get a sudden population boom of Coccidia does it cause coccidiosis.
It's not likely the bird.