Hi Ppabarr - instead of editing your original post I would suggest using the "post reply" tab. That way BYC will notify people that are subscribed to your topic (like me) that there is new information. It also makes it easier to follow your updates if the thread gets lengthy.
Usually with...
How old is Missy? Is she a relatively new layer? Has she been laying normally before this?
You should do a search for "egg bound" on the forums... there is lots of advice. Hopefully, she is just having trouble passing soft-shelled eggs. I have personally fixed this by giving Tums and a warm...