I did not manage to open her up. I tried. Between bee emergencies, the garden in the heat, the fact that I have almost no counter in my kitchen available, and didn't want more bad bacteria in it, and a knife that didn't really want to make an incision. and exhaustion. I did all the dishes, took her to my makeshift table out front, and just wussed out.
She is gone. I put her in the trash, rather than out for the coyotes (who I would like to stay as far from my house as possible). Hawks don't eat carrion, there aren't many vultures hereabout. Maybe I'll have had more than 3 hours sleep the next time a hen dies, but I have to save the lesson for then. And maybe look at a file or a video on how to...
Thank you all.
Gypsi