After reading a few more threads on here and getting up the guts to do it (had to remind myself that we butchered last Sunday, and I used to help the vet I worked for with surgeries...) I went ahead and did a necropsy myself. All internal organs were in great shape, gleaming and healthy, no lesions or strangeness of any sort at all anywhere. However, when it came to the digestive tract her crop was absolutely full, intestinal tract was totally full all the way through. found a section of intestine that was hard as a rock, about as big around as my thumb, and as long. noticed that the entire intestine was full, so cut it open to try to squeeze out the hard part, wouldn't squeeze out so I cut it lengthwise, pulled out the lining of a gizzard the size/shape of my thumb...from one of the chickens we butchered Sunday! followed her gut back up to her gizzard and examined inside of it before I realized what it was...thought at first it was a weird piece of leather or something. Note to self *lining of chicken gizzard is indigestible by other chickens*! Darn it all to heck! We even talked about whether or not it was ok to let them peck at the entrails. Decided liver, heart etc were ok, but not intestine/gizzard, crop etc. but didn't track down original gizzard from first chicken, was already gone. will know better next time and be sure to hit the bucket with everything but liver and heart.
also, fluid coming out of mouth was likely backup from very full crop (the size of my fist). There was also some fluid in her lungs, i'm thinking from the general stress on her body of the impacted gut, or maybe aspirated some of the fluids coming back up from her crop. anyhow, am very sorry I didn't know better and will never let chicken gizzard be eaten by chickens again.
i'm glad to know that there wasn't any disease though.
hope this helps some of you.
