How old is she? Is she thinner than your other birds?
Do you have a rooster with her, or did you have a rooster with her at the time this started? Did it start suddenly, or gradually? Were there any signs of trauma? Does she have weakness throughout her entire body, or only her backside?
What is her diet? Have you done any treatments?
Is she still laying eggs? Does she defecate normally? Is she acting different in any other way?
not sure how old she is but my guess would be 1 year + she is thinner than other hens , yes i have rooster with her all the time , ( 3 hens + rooster ) it just started suddenly , weakness only to her backside , mainly egg layers food and some grains every 3 days or so , i dont think she lay eggs , and yes she defecate normaly
she cant walk like normal hens , im guessing she got broken back?
did you check video? http://tinypic.com/r/2e2jd44/9
Hi @alfalahi Welcome To BYC
Your video doesn't work
From the stance that your hen has, I would suspect that she has an internal laying/reproductive disorder like Egg Yolk Peritonitis or Ascites. If the swelling feels like it has fluid in it, it can sometimes be drained to give some relief. A vet can assist you with the draining or you can try it yourself using an 18guage needle.
Keep in mind that draining can also cause further infection. Antibiotics are usually not that effective, but can give some relief for a short period of time.
I'm sorry, but this type of condition worsens over time and the outcome is not positive. There are many threads here on BYC and some videos on youtube about draining a hen that has a "water belly" or Ascites. It's also possible that she has a tumor or cancer, only a vet can possibly take an xray to know for sure.
If she is suffering, having a hard time breathing and losing weight - after you have tried supportive care - then the best thing you can do for her is to end her suffering.