Yes I definitely recommend opening her up if you can stomach it. There is a lot to learn. We love helping assess necropsies here: https://www.backyardchickens.com/t/729605/the-natural-chicken-keeping-thread-ots-welcomeSorry for your loss. You might consider doing a necropsy - either sending her to a lab or doing it yourself. Terry at www.hencam.com says she does them herself and learns a lot. I'm sure there are threads on BYC that explain how to do it.