chicken has been sick for two months

[yoongl3s]

hi i have never raised chickens before and she had parents of two different species but anyway:

my chickens butt area has been super swollen for two months now, if u touch it it feel like semi hard play-doh. she also started “throwing up” clear/ brown liquid. she still eats and drinks water but her poop is extremely watery. she also makes these wet clicking sounds(?) and i have no clue what that means, i have no clue how she has been able to he like this for this long, but i need help or advice :’)
she kind of just stands still to sleep, and she walks but only a bit or she gets tired. i have isolated her and gave her a new batch of food and clean water but i worried she might punch out soon

 

[FrostRanger]

Pictures?
From the sounds up it though, she likely has water belly. One can drain it to provide temporary relief but unfortunately the things that tend to cause water belly tend to be fatal and untreatable