Chicken with hard swollen lower abdomen

[Spambergg]

I need some advice. I have a 2 year old hen who has been getting increasingly mopey. Today she seems to be worse. She comes out and free ranges with the others but she tends to stand still with her tail down. Sometimes she struts around normally too. Occasionally puffs her feathers. Her lower abdomen(area between the back of her legs and vent feels swollen and hard. She had some poop stick to her feathers that was thick white with greenish black in it. It had a strong odor of urine which I thought odd. Her vent does have some red areas but the whole thing isn't red. She does eat some but not aggressively like the others. No other hens acting strange. Thoughts?
UPDATE:
She is eating and drinking today. She's out walking around and free ranging but moving slowly. Her crop seems to be much bigger today than yesterday. It's also definitely right sided.

 

[Yardfulla poopers]

It may be ascites. I have lost two hens to this as I am too afraid to try to drain the fluid with a needle. My one barred rock has survived it twice with the only difference being I added a couple chopped cloves of garlic to their water each time I noticed her having a problem.
Not everyone agrees with the garlic, but I've had much success with it.
I hope your girl recovers!

 

[Spambergg]

Update. Took her to the vet. She has peritonitis. They washed out her crop. Gave her two shots consisting of vitamins, antibiotics, steroids, and a GI cocktail. We will see how she does overnight.