4 yo Buff Orpington with swollen abdomen

[kasnelson]

My 4 yo Buff had a swollen abdomen for months, maybe 6. She died on Sunday (we stopped the suffering). Baths, deworming and VetRx didn't work. Her comb became floppy (unlike her) and pale with a purple hue. She wasn't egg bound. All my other chickens are fine. I did a bit of an autopsy and found the swollen abdomen was from gas. So she didn't have EYP or acites. She seemed to have a build up something. Maybe poop? It was light tan in color. But she was still pooping when she died. Any thoughts on what is was? Could I have prevented?

 

[kasnelson]

Here's a photo if that helps.

 

[kasnelson]

Sorry if this is a bit graphic!