I felt a hard "bump" on my hen - what is it?

[missypebble]

I have a Buff Orpington, who is over 2 years old. She hasn't laid an egg for over 6-8 months, and during the time that she did, she was laying an egg every other day or every 2-3 days for several months, then her egg production slowly came to a halt. I'm feeding her laying feed and free choice of oyster/ grit. I've also been adding ACV to her water on a daily basis. Unfortunately, she does not get enough natural sun light as I'm not able to let her stay out during the day time. She gets about 1 hour of natural day light/ day and about 4 hours or so 2 days out of the week. Her other sister, is a good layer, she lays an egg every other day and so with this, I'm assuming that it's not about the feed nor the day light that she doesn't get because if that's the case, her sister wouldn't lay as well. She has been looking healthy and normal, as far as I can tell. However, I do notice that her drops are compacted, small and rather on a dry side. She doesn't like to eat lots of vegetable and she doesn't eat much of her laying feed at all. She loves grains, sunflower seeds, millet, rice. I honestly haven't been good at making sure she eats her laying feed, and I think the only way to force her to eat it, is to take everything else away from her.
Earlier today, I decided to give her a warm bath so I could have my husband "feels" inside her vent. He couldn't "feel" anything, but, while I was drying her out with a hair blowdryer, and while rubbing/ massaging her abdomen, I felt a hard bump right next to her vent and only on one side.

My question is: that "hard bump" that I felt near her vent, is that something I need to look into, or have a vet does an x-ray on her to find out? Is that related to her not laying for over half a year? I thought I read somewhere in here that sometimes, if an egg does not pass nor if it couldn't form an egg, the yolk can get cooked inside the hen as the hen's internal temperature can do that - is that true? So does that mean my hen is in danger?

Can someone please help?

Thank you.

 

[missypebble]

I forgot to mention - I also noticed that when she tries to poop, she would just stand there and really, really, really pushing herself to push the poop out - it is as if she's in labor. Thanks for anyone's inputs/ feedbacks!