I was anxiously awaiting an egg from my hen, Tuvalou, which would hopefully be fertile, so I could put it under a different hen who is currently broody. That is why I happened to feel her bum, to see if an egg was imminent. It feels much larger than any of my other hens' back sides, and since she had spent several hours in the nest box without producing an egg, I thought she might be egg bound. But, the next day, she produced an egg. I felt her bum again, and it still felt very big - about "two eggs worth" of size back there.
She is behaving normally; still the first one down the ramp in the AM, and surely the most gluttenous of the chickens. The only difference I see, is that since the NOT-egg-bound incident, I have been watching her poos, and see that her droppings seem very runny; a big splurch of clear liquid with some poo solids in them. She used to have nice big normal poo bundles. She has laid several more eggs, and her bum still - whether an egg is imminent or just laid - feels huge, compared to the other hens.
Any one else have a chicken with a big butt?? Do I need to put a lubricated, gloved finger in her vent to check for some obstruction?