Egg Bound or Respiratory Infection? Help, Please!!

[Libz]

I honestly might do better at a necropsy than giving an injection, lol!
I don't like needles, nor causing pain...just not my forte. Got faint after the blood draw experience, and had to pep talk myself into giving the IM injection. Almost couldn't do it, a smaller gauge needle for that one would've been better- all I had was 20.
Give me a prolapsed vent or wound any day over dealing with needles!

 

[Libz]

1st video (48 hrs ago)

 

[Libz]

This next video is from tonight. I noticed her breathing seems to be very short, like she's only filling part of her airway. I dont know anything about chicken respiratory issues, but have started to wonder if she hasn't aspirated something?
(Note the throat area immediately under her beak.)

Or if whatever is causing the issue is more in her chest cavity than abdomen? Though maybe this is just what normal "labored breathing" looks like in hen.

She's usually not been this active. She perks up after getting out of a bath. Maybe in part the essential oils.

 

[Libz]

Sorry for the gross out final video, but in case anything looks "off" in this area...
Her vent hasn't been pulsing like this normally. I think it was because of pooping only. She'd just had another epsom bath, which obviously can give the runs.

 

[rebrascora]

I would entirely agree with everything Wyopr Rock has said.
My guess would also be that this hen has a reproductive disorder, possibly internal laying/ascites which has caused swelling in her abdomen which is compressing her rear ventral air sacs and resulting in limited air exchange and hence shallow breathing. If you watch when she walks, she moves her legs out slightly because the swelling in her abdomen is preventing them from being able to move normally.... it is pushing her hips out.
If you can be sure that she has been laying recently (in the past couple of weeks, then it may be salpingitis (an infection of the oviduct where it becomes impacted with lash egg material). If she has not laid an egg for several months then more likely to be internal laying.... where egg yolks drop into the abdominal cavity and build up and sometimes cause ascites. Where and how deeply did you insert the needle to try to drain her. The fluid collects in the very lowest part of the abdomen between her legs and will be just a very short distance (1/4inch or just a bit more) in.
It may also be a tumour.
Sadly there is very little hope unless you can afford to spend hundreds of $ which I know I couldn't. I would start researching ways to euthanize her so you are prepared when it becomes necessary. Only you can make that decision.
I would also encourage you to open her up after death and take photos if you can bring yourself to do it. I find it really helps me to feel at ease with myself when I find an incurable condition that was clearly causing her discomfort and improves my knowledge of chicken anatomy and ability to assess and diagnose problems in other chickens.
I'm sorry I can't really hold out any hope for your girl. It is really heart breaking, especially when they are young.