Growth on chicken butt

[Tastelikechickn]

Can anyone tell me what the heck this is? It doesn't seem to bother the hen and it is pretty solidly attached. It has doubled in size in the last week or so.

 

[sphinxface]

I have no idea what it is, but it doesn't look good, things that grow big like that never seem to be good... I hope it's not... good luck with it D:

 

[Eggcessive]

Where is the growth attached? Is it at the vent or near it? Can you take a close up of her vent and the growth?

 

[Tastelikechickn]

It looks like it is off to the right side of the vent. I only have two hens, and they were older when I got them and past their prime for laying. I'm not sure if the one with the growth is still laying, but I'm getting an egg about every day between the two of them. She is very active and is not acting sick. She doesn't seem to be bothered by the growth and is not messing with it.