Thank you everyone for your support - it really meant alot to me. I spoke with the vet this evening and got an update on the necropsy results - it was the right decision. She had tumors in her liver, kidneys, proventriculus, intestines and pancreas. Her liver was also 3-4x its normal size. She had a small grass impaction in her crop but my guess is that is just material that could not pass through because of all the obstructions. Her gizzard was also hugely impacted with grass material. Her abdominal air sacks were all but collapsed from what I understood from the mounting pressure on them. The oviducts and the rest of the organs were as expected.
Mareks was ruled out and the vet has taken pictures of everything and will give me a copy when I go to collect her body. They are also confident that what she had was not a threat to the rest of the flock and that I need not worry about it - it was an unfortunate play of genetics. I will still be careful though - the grossly enlarged liver is concerning and I will close my flock for at least a year to see how things play out.
The tumor growth over the last week was quite aggressive in hindsight - it literally moved the position of the enlarged gizzard towards the vent over 4 days, which was also the same time the respiratory struggles started. This probably also accounts for why nothing was seen on the first xray, it was not a good xray by any means but we should of been able to see at least some of this - so it may have grown exponentially over the two weeks of treatment I gave her in chicken hospital. Everything kind of adds up. The frustrating ordeal I had with coccidiosis with her was also probably attributed to the cancer, her body was not in a position to fight it off (it has been very wet here - so there would of been sporulating oocysts absolutely everywhere) and she was dependent on the medications to get rid of it. The fluid that started collecting in her airsacks was probably the beginning of the end and untreatable because her organs would of been ready to fail (my guess is the kidneys caused this). The mucous covering her poops were probably caused by the tumors/associated inflammation in her intestines, this also explains why they were often so narrow (though does not explain the improvement at the end). I am not 100% sure of the function of the pancreas but think it has to do with digestive enzymes - which explains why her poops were always such a deep green color - I was under the impression it was colored that way from the plant material. The cancer in the kidneys may have caused the irregularity with the urates - some droppings had a nice white cap on them, others were a watery urate mess. The cancer in the proventriculus would of stopped her crop from emptying as it should and caused it to back up. The cancer in her intestines would of stopped the gizzard from emptying and caused a backup there. The weight loss - while probably mostly caused from the blockages, would of been accelerated by the issues with the liver and her bodies inability to process and store fats (a month ago she was quite the heavy little girl), she had very black skin and eyes so unfortunately I was unable to see if she was jaundice and there was no evidence of bilirubin build up from her droppings (probably because they were so green - if chickens even show that).
I find it amazing - she had all this going on and only had one day where I was convinced she was in pain. All the other days she was actively walking around, hunting for bits and pieces, attacking anything that dared step onto her patio and acting like her normal self. In hindsight - her normal self may very well have been sickly and because it was her normal way of being - it did not strike me as odd. Even though she did have sass - she had never been a hyperactive girl, even as a chick (which is not uncommon) and I never saw her running around playing - she had more of a 'I'll come to you when I'm damn well ready' attitude and would ignore me and anyone else over the other more interesting things getting about. For reference though - her poops in the past were completely normal and healthy looking, this was the first time she had ever seemed ill - three weeks ago she had a bill of perfect health.
I will make a final post for this thread when I have the pictures and xrays in hopes it helps someone else out in the future. I will also make a post about clearing a gizzard impaction tomorrow when I have a little bit more time.
It is a bit of a tricky situation and a difficult one to fix -but she is still looking bright and has a good appetite (eating puréed foods and oils only to try to get things moving) so there is still hope.
Sometimes the best one can do is to end their suffering.
