What is this?

[srfrgrl]

One of my hens has a bulge under her vent. It has been getting bigger by the day but does not seem to bother her. Is it unlaid eggs? Or something else? Any ideas or suggestions are welcome.

 

[Eggcessive]

Can you post a picture? It may be that she is laying internally or she could have ascites (fluid in her belly.) Some hens develop these enlarged areas, and they can all be different. I have one ike that which has been getting larger for months. Does your hen lay eggs?