She had it over the summer, the black spot wasn't big - I sprayed with blu vote a few times because I thought it was from picking. I didn't notice it for a few months and now, there it is again. It is soft, below the vent. Nothing hard. I tried to draw out fluid and nothing came out, could be that my needle is too small. She is healthy and happy. I have no idea if she is laying or not. She is a Black Australorp - almost 2 y.o. Maybe an infection? Thanks for any thoughts!
It's difficult to say exactly what it is, maybe a cyst, hernia, teratoma, or even a reproductive cancer. Many hens have those types of enlarged areas and live for months or years, and many people will open them up after death just to see what's in there. If you do a search at the top of the page for "swollen area below vent" you will probably read more threads about similar growths.