No.
You aren't really going to find any hens (or roosters) that are aggressive to predators.
They are after all called "chicken" for a reason.
A predator secure coop and run would be far more effective as predator prevention than a fluffy laying hen.
Does she have any respiratory symptoms?
Infectious Coryza is a bacterial respiratory disease. Symptoms include coughing, sneezing, mucous, facial swelling with pus in the eyes and a very bad odor.
I'd start her on 300mg Calcium Citrate+D3 now, then once daily for a week.
I'd also go ahead and give the Amoxicillin. Dosing is 57mg per pound of weight given orally twice a day for 7-10days.
Figure out her dose or tell us how much she weighs.
Fish Mox in the capsules are not water...
Good advice from the others.
With her being hunched up like she is, I'd consider giving her 300mg Calcium Citrate+D3 for 3-5days to see if she expels any lash material or egg.
An enlarged and hard abdomen, can often indicated reproductive issues. Like mentioned previously, there's quite a few...
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Can you please provide clear, well lit photos of the hens and their vents?
You mention Prolapses. Do both hens have Prolapsed Vents?
IF so, then the white paste may be urates and residue which is commonly seen when there's Prolapsed Tissue.
Are you keeping the exposed tissue...
I'm not sure what you can do to help her.
Did the Sauna treatment help at all?
You could try Oxine therapy to see if that makes any difference. It may be that there is not anything that can be done and she'll manage with this Chronic Issue all of her life.
Take a bit of time to Explore her...
She's being plucked, mated (probably overmated) and may also be molting, it's hard to tell about molt in the photo.
I does look like there may be Lice Nits on the feathers in one photo, hard to see. I'd get a can of Permethrin based poultry dust, put it in a sock and use it like a powder puff...
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Photos are always welcome. Chicks, your brooder setup, the poop, etc. are always nice to see.
I'm sorry you had one that didn't make it, shipping stress can be terrible at times.
For the lethargic one, she is drinking a lot or not?
If you have any Poultry Nutri-Drench, give...
Could be Fungal Infection or perhaps some scaly face mites.
Looks like she's molting too.
It won't hurt to apply some anti-fungal cream/ointment to the skin to see if that helps clear it up.
Just do the best you can, see if she will come around by being in the sling.
Have you checked her over really well for any punctures, bruising, abrasions, etc. that are hidden underneath the feathers?
I'm glad she's slowly improving.
Have you ever tried giving antibiotics in addition to draining?
It has turned cool and windy here, later in the week dipping down into the high 30s. I'm not ready for that:)