She may be getting to the age where she is getting unhealthy. I would keep an eye on her and research her symptoms....I had 2 hens that egg bound on their first egg. Mine was from a line/breeder issue, I believe. I culled after 2 days. Your problem may just be due to the age of your hen. If she is ill cull her.
Edited to add: Some people do take their chickens to vet...I am not a person who will take a chicken to the vet. I don't think there is alot a vet can do to help a chicken and it just prolongs the suffering. research the gape worm....I don't know anything about that. Maybe some others with more experience will have some good info on that.
Edited by gg706 - 1/1/13 at 9:18am