Brahma with warm, swollen abdomen.

[micstrachan]

Hmmm… I hate to tell you this, but that body language sure looks like a reproductive disorder to me. I think you need to determine whether this bird is laying. Have you seen any soft/rubber eggs or fleshy looking things in the nest box?

 

[Wyorp Rock]

Is she eating/drinking o.k.?
Active?
Any lethargy?
Can you spread out the feathers and take a photo of what the abdomen looks like?

Is she molting?

 

[micstrachan]

Oh! Well molting is a different thing entirely. If she is molting, she is probably not ovulating. However the swollen belly will need to be addressed. It could be from an infection or something else.

 

[Wyorp Rock]

I haven’t seen any soft eggs, but I’m not 100% sure she is laying eggs.

She is drinking and eating, not as active as previous weeks but she may be molting as her feathers are missing. I will take a picture tomorrow morning since it’s dark out here.

She looks like she is molting to me, that would account for the patchy feathers.
It would be good to know whether or not she is still laying. Most hens stop laying eggs during molt, but it's not unheard of for them to lay a few during molt as well.

More photos would be good.

All you can do is monitor her really. Re-check the abdomen for fullness. If it's fluid filled, sometimes it can be drained to give some relief.

Molting in itself is going to make her not feel that great. I would give her some vitamins once a week (the whole flock can have them) and some extra protein treats - eggs/meat.