Below I posted about a sick chicken. I just thought I'd provide an update. Yes, she did have egg yolk peritonitis. Unfortunately she was growing thinner by the day and was clearly in a lot of discomfort.
Graphic description follows...
When I post mortemed her I could easily see the creamy yellow smelly substance (a sign of infection) throughout her cavity and covering most of her organs. The peritoneum was thickened and discoloured and her intestines showed signs of pinpoint haemorrhages which are possibly due to pathogen overgrowth in the gut wall, or may be a secondary condition (such as coccidiosis due to immune overload). There were no signs of Mareks or tumours, and there were no worms throughout the length of her intestinal tract. Interestingly her caeca were massively enlarged (these are two blind pouches toward the end of the intestines). Her reproductive system seemed to have virtually disintegrated.
Poor sick girl. She would have been in terrible pain. Here she is in brighter days...
Fortunately the other girls are all well. Here is one of the deceased pullet's sisters, my favourite in colour and type:
My first sick chicken in a long while... She's a 25 week old pullet, one of the ISA brown x malay games. And she's not all that obviously sick — just a little light in weight, and off the lay. Yet her comb is red and her vent looks like that of a laying bird (i.e. moist and fairly wide).
But when I look at her in the yard I can see she isn't feeling well. It's hard to put my finger on what it is, but the main thing is that her head tends to stay tucked in. She doesn't forage quite as well as the others and a few times I've seen her sitting in one spot, head tucked in, eyes closed. This has been going on for a few weeks (ever since the goshawk attack on the flock) so it's time to give her a thorough going-over. She doesn't tuck her tail down (common with intestinal pain) so that's one good thing, I suppose. Even so, egg yolk peritonitis is a possibility.
Egg yolk peritonitis can happen to birds that should be laying but aren't producing eggs. Sometimes the eggs break inside the bird and encourage bacterial growth in the body cavity — usually this is non-recoverable. But usually there are symptoms like constant dribbling out the rear end and stained feathers. My pullet has nothing like that; indeed her bottom is clean and fluffy. Nevertheless EYP is something I have to watch for, since there have been a few soft shelled eggs under the roost, presumably from this girl.
I'm not sure which way this will go, but I don't like to see her suffering. I've separated her and will make sure she gets her share of the food in case that's the problem. I'll also be better able to watch her diet and intake when she's separated, and I can up the calcium in her feed. It will also be easier to watch her droppings in a small cage.
It's not a hopeful development. It may be that my phosphorus-calcium ratio is out, and the soft shelled egg laying has stopped her feeling well without progressing to full-on EYP; or it may be that she has some underlying congenital disorder or even visceral Mareks. (I haven't yet had the joy of a Mareks outbreak... Presumably at some point I will.) She might possibly have a tapeworm, so I guess I've got the option of using some Panacur (a sheep drench that can also be used to treat tapeworms and other worms in chickens, with careful holding periods). However I don't like using wormers without other symptoms like diarrhoea, so the responsible thing to do would be to first check her droppings for worm segments or eggs.
If she has a tapeworm treatment will be easy; if it's something more ominous it will be a different, sadder, story. I suppose she might also have been injured internally by a goshawk (since she first became sick on the day of the attacks). I gave her a once-over by torchlight, but it wasn't very thorough and perhaps I need to check her over more fully today.
So I have a few things to do with this poor girl. In the end it may be she has some underlying problem and it may never be found; these things happen. Nevertheless when balancing a home ration, there are many things to get right, and it's important to investigate any illnesses.
All my other chickens appear well and are laying nicely shaped hard-shelled eggs. That's a good sign regarding the ration. And the chicks in the tractor still appear to be doing well on a modified version of it (with rolled oats, bandsaw dust and kefir).
Let's hope I can find out what's ailing the pullet, and that she mends!