I noticed yesterday that one of my Barred Plymouth Rock hens (2 years old) was breathing a little heavier when she was resting on the ground. When I felt her abdomen it was swollen and firm, but there also appeared to be fluid inside. I also felt a hard, firm object--whether it's an egg or tumor I'm not sure. The hen has been walking around actively, eating, drinking, pooping, etc. I put her in a warm bath and gave her calcium to see if she was eggbound, but no results. Today, she hasn't changed in her behavior and her abdomen doesn't feel much more swollen than yesterday. I inserted a gloved, lubricated finger into her vent to see if I could find anything and again, nothing. Any ideas as to what this may be?