Thanks all for posting to this thread. Although the information is dated, it was very useful. We have had about 6 chickens die in the last year from unknown causes. We lost another one today and I was more than concerned by this point. I decided to to a necropsy and found exactly the same thing (not knowing what I was looking for until I started pulling out the large masses of the yellow/whiteish hard substance). I immediately thought tumour, but now understand the issue a little better. Being in Canada, we have a little different conditions and extremes that I thought played a role. All of the chickens that have died were from the same place (not a hatchery, but a chicken farm) so I'm not sure if genetics played a role, but could very well be the case. At any rate, we have been doing everything we can to keep the coop clean, keep the chickens healthy and not forcing laying. The article about extending the light times was great as we were just about to do that thinking it might help. I guess it's one of those things that is part of having chickens. The breeds that were affected were Isa Browns and Leghorns. I could post pictures but they are pretty much the same as the ones that were posted...it's crazy how much of that mass came out of that hen!
This is a great forum, and we use it all of the time to solve our chicken problems! Thanks to all of the contributors!
