One of my six hens has a large growth (see pix) on the front of her breast, and it hangs and sways in front of her as she walks. It was there a few months ago, then it seemed to deflate, and now it's back. She is not acting sick at all, and even picks at her own feathers on the growth, as some are now missing. I have not treated her with anything. The others are not showing anything similar, and they all get along fine, though she may get pecked on once in a while, but very rarely. Can anyone give me an explanation of what this might be? I've had chickens for about 6 years now and have never experienced anything like this. Because she doesn't act sick, I haven't stressed in trying to do anything for her. Not sure if I should even attempt to fix this, and not really sure if she is laying eggs, as I'm getting a few a day now. And do you think the eggs may be affected in any way? I have not seen any problem eggs so far. Thank you.