I have a older hen on the yard yesterday she looked different I picked hen up and her body was swollen to the point I thought she would pop. Never seen that before. Her head, legs,face were fine but her breast, abdomen were swollen. does anybody no what causes that and how to treat it.
Sounds like some kind of ascites (fluid build-up due to varying causes). I have read lots of people drain the abdomen with a needle and syringe to draw the fluid out but have never done it. There are threads about it with more details about the supplies/needle insertion if you search for "ascites" on this site. I have read ascites is usually chronic. From what I understand, you do need to drain the fluids or it is fatal. The fluids put pressure on the internal organs, including lungs causing difficulty breathing, and the skin may rupture. I have not dealt with this problem personally, and this is just a guess. Good luck.
Is the crop full and swollen as well as the lower abdomen? Could there be a leaking air sac that has left air under her skin? Does er crop empty mostly overnight? Crop problems can make the chest look huge. Water belly or ascites can make the lower abdomen feel like a tight drum. There are many causes for that including cancer, internal laying, and heart failure. Pictures of your chicken may help. Below is a hen with ascites.
ascites (note the vent at upper right)
Here are some threads to help you if you need to drain the abdomen: