@Wyorp Rock
Thanks for tagging me. I had been following the thread(for some reason I hadn't put it in watching though so I appreciate the nudge) but you had it covered, so I had nothing more to add until those final photos.
@LindaNL
I'm so very sorry that we were not able to help your girl but I hope it is some comfort to know that you absolutely did the right thing to have her put to sleep. That is salpingitis and that mass of lash eggs in her oviduct must have been extremely uncomfortable for her and there is no way that she could ever have passed them, so you saved her from a slow and painful death.
Salpingitis is where an infection occurs in the oviduct. Sometimes it can be caused by a thin shelled egg breaking inside the hen or a hen that perhaps lays extra large eggs losing some of the elasticity of her cloaca and some faecal material entering the oviduct as a result. The infection generates puss which in chickens solidifies to a cheese like consistency. This is believed to be a mechanism by which the chicken's body prevents the spread of infection to other areas via the blood stream. Unfortunately this means the chicken does not appear sick and will continue to ovulate and deposit egg yolks into the oviduct on a daily basis as normal, but the egg yolks cannot get past the blockage and themselves become part of the cheesy infected mass, causing her to become backed up. For the first few day she may strain to try to pass them, but their irregular shape and increasing size make that all but impossible. Occasionally the first and smallest pieces are expelled and people find a "lash egg" in the nest box, but usually things happen pretty much without any obvious sign until it starts to obstruct the bowel and the bird becomes noticeably unwell as the digestive tract backs up.
This will probably have been going on for a week or more, whereas, if a bird is egg bound with an egg stuck in the cloaca, the bird is usually not able to poop at all and gets backed up very quickly... a matter of 2-3 days can prove fatal.
Internal laying is where the daily egg yolks released by the ovary fail to travel into the oviduct and instead drop into the abdominal cavity. There they build up amongst the intestines and liver until they put pressure on the organs like the liver, heart, lungs and intestines but this can go on for months and even over a year, depending on how prolific a layer the bird is. Sometimes they become infected resulting in Egg Yolk Peritonitis but often they don't. When cut open during a necropsy, the egg yolks have usually, mostly solidified and fluid from them leached out and settled in the lowest part of the abdomen forming ascites (water belly). Birds suffering with this often become incredibly heavy as well as bloated.
Anyway, sadly there was nothing that could have been done for your girl, but it is really helpful that your husband managed to open her up and take photos so that we can all gain a little more knowledge and experience through her.
Reproductive problems are the price that chickens pay for being so prolific with their egg laying. They did not evolve to this level of production but were selectively bred by man. Their system has not had the chance to developed to the point where it can take the wear and tear that daily laying 24/7 throughout the year puts on them. Breeds that have retained some of their natural instinct for broodiness and don't lay through the winter are less likely to develop these problems because their reproductive system gets regular breaks from egg laying..... perhaps something to consider if/when you restock. That said there are different problems that can affect other more broody birds, so there is no simple answer. Sadly, chickens are prone to many disorders and losses are inevitable sooner or later. Most of us know how heart rending those losses are to the loving owner and here at BYC we are here to help where we can and console when we can't. You could not have done more for your chicken. I'm so sorry we could not help you fix her.