Is this wry neck or something else?

I have a light sussex hen who is almost 2 years old. She is very underweight compared with her sibling (but has tended to be on the smaller side when healthy too). She hasn't been the best layer and hasn't laid for about 6 months (but we don't necessarily mind as she's more of a pet).

She has been unwell off and on, has not seemed the most healthy hen for quite some time, and has recently moulted/. I thought initially (several weeks ago) the moulting was a cause for her being a bit unhappy but her feathers are now all regrown, however she is not preening as the new feathers are all developed but those near her tail are still in the feather casing. She has a strange stance, head held up awkwardly, backside down low. Walks slowly and not much, sometimes a bit unsteady on her feet, appears weak. Looks and feels as if she has almost no breast, which relates to the underweight issue (appears almost like an indian runner duck in stance). However she seems to be eating (Barastoc layer pellets, scrambled egg, sunflower seeds, grass) and drinking fine with a very healthy appetite. She'll gasp a bit after gobbling up too much in one go. And she is defecating normally, though droppings are sometimes greenish. Her crop seems to be filling and emptying as normal, though it is smaller than the other hen's. Her neck is very strange looking but it is not twisted to the side or curved backwards like other photos of wry neck I have seen. There are no other signs of injury, she does not have worms or lice/mites - I treated coop and birds for both a month or so ago. Her neck has some right angles (90 degrees) but I don't know if her neck is just more prominent because of the underweight issue (ie. no fat around her so it stands out).

Recently she has been sitting down most of the day in the corner of the coop with her head and neck stretched straight out in front of her, resting her neck and beak flat on the ground, and closing her eyes sometimes. When she is not sitting in this, she sits on her haunches. Her comb/face are sometimes purplish tinged and she appears to be breathing through her beak, though her nostrils are a bit moist they don't seem too congested. She sleeps on the nest, never roosts, and rests her head straight out in front of her on the ground.

This morning she didn't get off the nest where she slept, so have brought her inside in a box to keep her warm and keep a closer eye on her as I think she is going downhill quickly. I don't have access to a vet that will see chickens. I'm in Australia so many of the poultry medications readily available in the US aren't available here, unfortunately, so home remedies, or things that can be found in a supermarket/pharmacy are my main option in the immediate term.

Attached are pictures (she is standing upright in these photos, and the bump in her neck is her neck bones, not her crop).

Could this be wry neck? Is there anything else that it could be?

She could be suffering from a reproductive disease such as internal laying or egg yolk peritonitis, but she has so many symptoms of wasting, sitting on her hocks, and neck symptoms, that she may have something neurological such as Mareks or vitamin deficiency, too. I would give her vitamins in her food or water, such as human BComplex or poultryi vitamins, and consider putting her down if she seems in pain or miserable.

Dang Lauree, that was one of the most well detailed posts i have ever read. I wish I had somthing to offer regarding her ailment, but a description like that is sure to get more good (like the one fron eggsessive)answers to your question. Good luck...

Thanks Jemezhens and Egcessive, I've been researching mareks and b vitamin deficiencies, and going to try some b vitamins. I think I have ruled out wry neck and am putting the neck weakness down to wasting and possibly lymphoma. Mareks is such a minefield, it seems so difficult to diagnose (without blood testing or autopsy) but I can't rule it out. Nambroth's article has been very helpful in educating me though.

If anyone has any other thoughts or advice from a similar experience, please share.

If you live in the US, you can try to get a necropsy done on her if she dies, to find out what was wrong. The body would need to be refrigerated in a plastic bag, but not frozen. Do a search for "chicken necropsy" and look for Metzger Farms, and also look for your state Dept. of Agriculture. With her pictures of upright posture, she looks much like a hen with internal laying or egg peritonitis.

Thanks eggcessive. I am in Australia unfortunately but there may be places here that do it. With the egg peridontis, would I be able to feel an egg? I did try the internal exam but felt nothing. She hasn't laid for at least 6 months, maybe more, but was never a daily layer even in her peak. She's still alive but breathing is becoming an issue. She isn't hot (it's winter here) but is clearly breathing with difficulty through her beak. When she eats and drinks it's worse! Like gasping for air as if the food/water has caused a blockage. I think I might have to put her out of her misery soon... I have never had to do it before so I am not looking forward to making that choice but it's not fair to keep her alive if life is such a struggle, and I can't do anything to help her.

Ok, I've researched peritonitis and it could well be that (for the sake of my other hen, I would rather it be that than mareks). Particularly given the fact she hasn't laid an egg for so long! I'm going to feel her abdomen to see if it's hot/swollen. Any other home checks I can do for it?

I also hope it is internal laying or egg peritonitis instead or Mareks. Here are some good articles to read:
http://www.chickenvet.co.uk/health-and-common-diseases/egg-laying-issues/index.aspx
http://scoopfromthecoop.nutrenaworld.com/tag/laying-issues/
https://www.backyardchickens.com/t/526089/egg-yolk-peritonitis

thank you guys for your help. am also learning from it.
big ups