I have an ISA Brown hen that is about a year old. She is a good layer and very active. Today she stood outside the back door for a very long time without moving much. I noticed she looked like she was trying to push something out her vent, but nothing is coming out. I caught her and looked at her vent. It looks enlarged, but not inflamed. She feels full and round but nothing feels solid like an egg. What should I do? she is not eventrying to get in the coop when I feed the other chickens. I do not want her to die so I want to try to stop what is happening as soon as possible.