Smells dead, wet bottom

[Sugar Chic]

A few weeks back one of girls was fluffed up and crouched in my flower bed. I picked up and found maggots under her vent. I soaked her in Epsom salt- used vetermycin and quarantined her and she perked up.
Fast forward a week later, I found another bird lying dead in the coop that showed no signs of illness. A week later and another passed away in the coop. I noticed today that my largest hen was not with the others and I found her fluffed in the flower bed. I tried to pick her up but she still had speed. I noticed her later in the coop looking like she was panting- her feathers are wet under her vent and almost look black, like blood. She smells like she already died. I tried to catch her so I could soak her but again she is still quick.
I’m pretty sure it’s already too late for her.
Coccidia or flu?
I can’t catch her to quarantine her- I have 3 other chickens .

 

[Wyorp Rock]

I noticed her later in the coop looking like she was panting- her feathers are wet under her vent and almost look black, like blood. She smells like she already died. I tried to catch her so I could soak her but again she is still quick.
I’m pretty sure it’s already too late for her.
Coccidia or flu?
I can’t catch her to quarantine her- I have 3 other chickens .

No, doesn't sound lie Coccidiosis nor the Flu.
Sounds like she has FlyStrike.

I would do out after dark when she's roosting, get her off the roost. Bring her and access her.
If she has maggots, then you will need to clean them off. Repeated soakings in soapy water can often make the maggots fall off. But be sure to pick off any you see.

Do you have photos of your coop/run setup?
Are your girls getting poopy butts or ?
In warm weather, flies can lay eggs on soiled feathers, once the maggots emerge, they look for tissue to consume and this unfortunately would be the hen. Flystrike can kill in a short period of time.

A few weeks back one of girls was fluffed up and crouched in my flower bed. I picked up and found maggots under her vent. I soaked her in Epsom salt- used vetermycin and quarantined her and she perked up.
Fast forward a week later, I found another bird lying dead in the coop that showed no signs of illness. A week later and another passed away in the coop. I noticed today that my largest hen was not with the others and I found her fluffed in the flower bed. I tried to pick her up but she still had speed.

 

[Susan Skylark]

Do you have a mean chicken, predators or poky wire/nail etc that your birds are getting wounded/injured on? Flystrike usually requires an initial injury to give the bugs access to the tissue (or wet/dirty/prolapsed/swollenmucus membrane or body orifice like the vent)? The death smell is tissue necrosis, dead and rotting tissue, usually means nasty bacteria along with the fly strike. Get some penicillin into her asap, use catron fly spray in maggoty wounds, look for the source of your problem to protect your other birds.

 

[Sugar Chic]

We lost her. She passed and then the following week another hen was stricken by fly strike as well. I soaked and dried- got maggots off her. But she passed the following day. Each one was struck on their bottoms. I have 2 more girls- they are ok for now- clean bottoms, and I’m keeping an eye on them.
There are no exposed wires or nails in the coop or near the nesting boxes.

Coop is clean.

They free range so perhaps they found a spot do their dust bathes that is hurting them?

I don’t know.

 

[Eggcessive]

Flies spread fly strike in warm weather. I would check all of your chickens vent areas for droppings. Clean them off in warm soapy water. Look for any wounds from pecking or a rooster spur. These are the ways chickens get it. Is it muddy where they are kept? Are they on bedding or sand? Are they picking on each other? Do you need to do a coop clean out? Permethrin spray is very good to use around a chicken coop to get rid of flies. It lasts 30 days. Let it dry for a hour before letting birds back in. They sell Martins or Gordon’s permethrin concentrate in inexpensive pints or quarts at tractor supply. You mix 1 tsp/5 ml per quart of water and use in a spray bottle or garden sprayer. Something is going on, and you could lose all of your birds with a painful death. Sorry for your loss.

 

[Wyorp Rock]

We lost her. She passed and then the following week another hen was stricken by fly strike as well. I soaked and dried- got maggots off her. But she passed the following day. Each one was struck on their bottoms. I have 2 more girls- they are ok for now- clean bottoms, and I’m keeping an eye on them.
There are no exposed wires or nails in the coop or near the nesting boxes.

Coop is clean.

They free range so perhaps they found a spot do their dust bathes that is hurting them?

I don’t know.

Sorry to hear you lost her and another one.

Do you have photos of your coop/run and the spot where they are bathing?