Hen acting strange?

[Fanny's Mom]

This morning Fanny was still sitting right where I left her last night. All the others were gathered around the heat lamp. When I came into the coop, she left the nesting box, but scrunched herself into a corner on the floor. I think it's her way of telling me to leave her alone, but she's really got me worried.
I failed to mention that two days ago while they were free ranging some critter got at them. At the time it seemed no one was injured. . .they were just all hiding in the bushes and Fanny was so scared I had to carry her back to the coop. The others returned on their own power. New Years Day she seemed fine. I didn't see her at all yesterday until about 6 pm last night when I diiscovered this latest problem.
I meant to say her problem last year was that she was egg bound (sorry I didn't unse the proper terminology). Murray McMurray advised me that that happens sometimes in young hens (that was her first year). If anybody needs it, I found a great thread about how to help an eggbound hen in the Emergencies/Diseases/Injuries and Cures Section of this forum. I printed it out for myself!
If anyone has any ideas why her rump would be all swollen when she's not carrying an egg, please let me know. I'm also worried about when she does develop an egg. . .think it'll probably complicate things.